From what I know, their main cause is overall just and they have done good work infiltrating places with hidden cameras and recording/exposing animal cruelty...
...But their publicity stunts, probably the big thing they're known for these days, are almost always stupid and imo do more harm than good by turning potentially sympathetic people against them, and possibly by extension animal rights.
Only reason PETA doesn't do ALF shit is to avoid legal troubles, but they still funnel money in their direction sometimes on the down low.
PETA and ALF are symbiotic, they perform different functions that are mutually exclusive for their organizations.
PETA can do big out in the open organizing, and can get celebrity support, because they are not openly eco-terrorist.
ALF can do cool stuff, but are unable to advertise, file lawsuits, do peaceful demonstrations.
Watch this and tell me PETA are libs: https://www.youtube.com/watch?v=_kfBFMhdaMI
Also this posted below: https://www.peta.org/about-peta/victories
Uncritical support for PETA.