Be careful about listening to self confessed YouTube 'guru's like the hodge twins. They aren't intellectuals and whilst mean well, they often have blaring holes in their understanding. They are ok for entertainment value but I personally wouldn't follow anything they said. They have decent physiques, but there is no way to know if they just have good genetics (anything works) or hard gainers that know how to train.
This is all neither here nor there, but the 'gurus' that I've talked to that have devoted their lives to muscle building seem to agree on the high reps for legs. The crowd I train with certainly prescribe to this. In fact 50 (yes FIFTY) rep leg press comes up in programming fairly often. 15-20 rep squats are also common (very painful). I feel the white hot pain in those let me assure you! Last week I did 50-40-30-20 reps on leg press. Very painful. I realise this sounds NUTS for someone that has only ever trained in the 12 reps or under ranges.
If wikipedia is to be believed, there are predominately type 1 fibres in postural muscles which matches exactly what you said. Since type 1 fibres are endurance tuned, you would definitely aim for fatigue over higher rep ranges to induce an adaptive response. Legs in humans contain closer to 50/50 white(type 2)/red(type 1 & 2) muscle types which matches the kind of training I've been doing. Squats can be as high as 20 reps and as low as 1. Whether we like it or not, we walk around on our legs all day and therefore there are always going to be type 1/2 fibres there and they have to be trained.
So to try answer your question, I'm not sure who is advocating doing the same old rep ranges all the time and on all body parts, but I would definitely train hard in a variety of rep ranges. I know as I look around my gym, its the guys confined to their 3 sets of 10 (pick a number) month in month out that grow the least. The single best thing I've ever done is to allow myself to rep up to 20 (and beyond for legs). After 3 years of stagnated training, I was able to gain 6kg (13lb) of muscle in 5 months once I learned how to train properly.