>>56931809I'll provide a brief rundown in one post.
Because all stats are maxed out in gen 2 ou, things are both bulkier and stronger than they are in other gens.
It isn't merely the fact that Snorlax is minmaxed and has only one weakness---which is not merely predictable but also rare---but it has access to a wide and versatile movepool that makes it both unpredictable and dangerous---moves which many mons don't get, and not all are able to take advantage of.
It has Flamethrower/Fire Blast and Thunder for its defensive checks (as well as Earthquake for most of the rest), it has Curse to make it both stronger and bulkier, it has Belly Drum to instantly raise its threat level, it can take good advantage of resttalk, it even has Lovely Kiss to status enemies.
It's not that Snorlax is broken per se, it's that the ways to check it range from unreliable to piecemeal (e.g. growl and nightmare strats). But it's not an instant win because of 4mss.
As for the stall talk goes, the bulk and resttalk mechanics play into that experience heavily, but even more, it's because the movepools are so barren and underpowered that depending on the matchup, making progress against certain teams with certain defensive cores can be excruciating. But that's the fault of both teambuilders; you can easily choose teams that never lead to you having to deal with long or overly long games.
