Permissive licenses (MIT, BSD) prioritize programmers’ freedom, letting them do whatever they want with the code including keeping their own changes proprietary.

All variants of GPL are copyleft, which prioritizes end uaers’ freedom to control the software they use.

LGPL is for people who want the subsystem they’re working on to remain free, but don’t mind it being incorporated into proprietary software.

GPLv2 is for people who want to preserve users’ rights to control the whole program.

GPLv3 is resistant to Tivoization, i.e. to preserve users’ rights to actually run the program on the hardware it was intended for.

AGPL is resistant to circumventing users’ rights by using SaaS instead of letting them run it locally.

(BTW, everyone who thinks there’s a good reason to prefer GPLv2 over v3 is shortsighted and wrong.)