I bear you no disrespect, Mr. @rsob, but I cannot see the slightest sensible justification for this position.

If there is no turn lane (and on most road there is not,) that That is Exactly the situation in which one should take the lane. One takes the lane to prevent vehicles from trying to overtake on the left in any of a number of situations in which having a vehicle overtake on the left would be problematical.

Might I quote the Florida Traffic Control Statute section 316 (this is the same wording used in almost every other state ... I have ridden in over three dozen, as I count (not a math major, but still) and checked the laws for each:

5)(a) A person operating a bicycle upon a roadway at less than the normal speed of traffic at the time and place and under the conditions then existing must ride in the bicycle lane or, if there is no bicycle lane on the roadway, as close as practicable to the right-hand curb or edge of the roadway except under any of the following situations:
1. When overtaking and passing another bicycle or vehicle proceeding in the same direction.
2. When preparing for a left turn at an intersection or into a private road or driveway.
3. When reasonably necessary to avoid any condition or potential conflict, including, but not limited to, a fixed or moving object, parked or moving vehicle, bicycle, pedestrian, animal, surface hazard, turn lane, or substandard-width lane, which makes it unsafe to continue along the right-hand curb or edge or within a bicycle lane. For the purposes of this subsection, a “substandard-width lane” is a lane that is too narrow for a bicycle and another vehicle to travel safely side by side within the lane. (https://m.flsenate.gov/Statutes/316.2065)

The freaking Law says that if you are taking a left with no turn lane, you have the option of taking the lane. With more than 50 years of traffic-avoiding experience (most of it involving daily rides) I can attest that taking the lane fro a left turn makes a world of sense.

If there is a turn lane You Don't Have to "Take the Lane." You just get into the turn lane. And if I ama in the turn lane I would Still signal, if I could.

Using common sense .... if I am riding downhill rapidly and want to take a left turn, I have three potential risk scenarios.

First, a car could be coming out of the left-hand side street and turning in either direction. If the car is turning right, it should never cross the path of the descending rider, but I wouldn't trust the driver. If the car is turning left, into the lane I am occupying, so long as it turns first, I am fine.

Second, there is oncoming traffic, in which case, I cannot always safely turn from anywhere on the road surface. That is a simple judgment call, as to whether the closing speed allows me time to make the turn. If I have enough room, can turn from the far right edge, clip the apex and end up at the far right edge of the side street ... maximum efficiency. If the oncoming car is too close, I simply cannot turn safely anywhere in the travel lane.

Third, there is a car or cars closing from behind me, which might try to pass on the left as I slow. THIS is exactly why I would take the lane. I can see the cars in scenarios One and Two ... but I cannot watch the cars behind me so the only way to work with them in a safe fashion would be to ... Take The Lane. The cars can pass on my right if they are that impatient.

This is also problematical, because you would be crossing mid-street ("jaywalking") and cars might not see you. it is however a valid option, so long as you manage the risk.

There is a particular left turn on a route I often ride, which is just over the crest of a nice little hill (something most of you here wouldn't even cal a hill, but whatever ... I am old and fat and weak.) Because the runt is over the crest, it is on the downhill, and sweeping across the road and clipping the pax as mentioned above feels really good (I get a little Boy Racer frisson if I hit it right.) However, since it is over the crest, taking the lane is problematical---a car cresting the hill might not expect to see a cyclist in the left-hand third of the lane. There is a stub of a side road on the right ... about 20 feet of pavement for a road which was never finished (I guess a development went bankrupt before it was built.)

Because I can position myself perpendicular to the main road, which gives me excellent lines of sight, I have no issue pulling into the stub road on the right and then crossing. I can be fully off the road, ready to roll, and see in every direction.

If I were on the side of the road trying to look uphill over my shoulder, and trying to launch downhill and turn ... I would feel less safe. To each his own.
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Here is an option no one seems to have considered: Slow Down.

If the OP knows he needs to take a right tun partway down the hill, why not brake intermittently so that you can approach the turn at a speed which permits safe signalling?

Why? Because the thrill of riding fast is greater than the desire to signal the turn?

if someone assays to me, "I cannot ride safely and go fast at this point in my ride," I would say, "Slow down." Seems sensible. Slow down Before the turn, so that you are not braking so hard that you are in fear of safely signalling the turn.

Or, accept that you crave the thrill of the speed more than the possible added safety of the signal, and go for it.

So long as the speed at which you ride you bike is totally in the control of You, the Rider, you cannot complain that you are going to fast .... only that you are not riding smart enough.

Well, that is one possible point of view. Whether it works for anyone is not really important. it is just an opinion.

But consider this ... if you were taking the lane, and a car came up behind you, and, without signalling, cut sharply from the outside of the right lane, across your path, to make the same turn you were about to make .... and sad, "Yeah, sorry, I couldn't signal, I was going too fast ... " how do you think people would view that?