I would disagree with that statement. As long as you know what you're getting and it's intended purpose (i.e. - you are not looking for a high end racing frameset), there is nothing wrong with thin-walled (1.0-1.2mm or so) hi-tensile steel tubing. That is not the same as the heavy tubing used on department store bikes back in the day. Those frames welded (arc-welded?) and needed very heavy tubing to withstand the weakening inherent in the high temparature welding process. "Good" quality bikes (under $200 in the early 70's) used thin-walled hi-tensile tubing extensively and were typically brass brazed with lugs. The weight penalty is 2-2.5-lbs depending on tubing and frame size. With aluminum rims and crank you can build a very nice riding machine out of a fairly entry level boom period bike that will weigh in around 24.5-lbs. And those bikes often had somewhat more relaxed geometry and longer wheelbases than their high-end racing brethren so for a casual bike for cruising around town, commuting, or riding the MUP they are worth a look.