Because that's a thing I've seen in several 5e campaigns. Games falling apart that fast. Level 1 stretched out over 3-5 sessions. Brutally hard combats that reward paltry XP. DMs effectively forcing a TPK by (as noted) having us get jumped by bandits during our second short rest we've ever taken.
Some of the OSR has a lot to answer for. Why do I say that? Because there's a section of the OSR that promotes this sort of toxic DMing. Long, long stays at first level. Brutal combats. And no experiences to make new players want to stick around.
D&D should be challenging, and I'd love more advice in the core books on designing adventures for different levels. But that level of DMing? No thanks.
Cheers,
Merric