It should mean that you get kicked if your ping is bad for a while as it ruins the playing experience for other players. If you don't agree with this, you clearly don't care for other players who spend a lot of money on their internet providers which, in my opinion, is incredibly selfish of you.
OK don't play a Mexican server, play an American server instead, your connection will be much better there meaning you won't be ruining the gaming experience of players there.
Rejoin is a waste of time. If you crash you crash, that's the way it always has been. Developers would have to set a unique time limit for every single game (each would have to be different, because some games are fast some games are slow), make sure it is balanced (many weeks of testing would be required), they'd have to create a mob or NPC to replace you whilst you're gone with your exact health, potion effects and inventory (and if they didn't, you could just log off to avoid death technically...). On top of that, if your internet crashes it will take at least 3 minutes to get back on, by that time people will have killed you anyway so there's no point of rejoin. Crashing isn't big enough of a problem to add a rejoin feature for... and if you're a player who crashes a lot then clearly the issue is with your PC/internet and not the server, very selfish to make developers go through this much trouble just for your bad hardware.