Driving in to one ATG arc does not warrant losing a 100% hp light tank in 4 seconds.
None of the light tanks necessarily die to two shots of any regular anti tank weapon (i.e. Pak 40, Zis, Raketenwerfer). These do 160 damage per shot, and the Stuart and Luchs have 400. There is no situation whatsoever where they can get two shotted by these, save Mark Target. Several patches ago you could do it with AT gun + For Mother Russia, but now team weapons don't get a damage boost on activation of ability so that isn't even possible now.
T70 can get two shotted, since it has 320HP, but it also has a self repair ability that works on the move. In other words, you charge in with your light tank blindly, which you shouldn't do in the first place, take a hit, hit the self repair button in the 3 seconds before the next shot, and you will survive the next hit, absolutely guaranteed.