I have never had a reasonable cholesterol reading. This despite seriously throwing myself at cycling for the past 10 years. Some doctors have said - gee whiz, you're so active, don't worry about it, others have been concerned. My current doc is recommending statins and I'm reluctant (currently about to start treating hypothyroidism which is known to elevate the cholesterol readings.)
When I received my most recent test, I went back and looked at my diet. I doubt I surpass the total daily recommendation in a full week of eating. So it's almost certainly genetic, especially when you look at my triglycerides which are in the range of elite performance athletes (which I am far from in actuality.)
You're right - everyone is different. Some can eat poorly, live on the couch and never see a bit of problem. Others can exercise like mad, eat properly, take all the correct supplements and still end up on medication. It seems to be the genetic hand you're dealt.