Next PETA will be lobbying for animal suffrage.
Dictionary entry for "slippery slope" fallacy. Ridiculous 'right to vote' != anti-suffering.
Legally, this is without merit. Animals are given no constitutional rights.
What it is is a 'protest' to give attention to the moral issue, which has plenty of merit.
The same sort of thing could have been done to oppose slavery, when legal challenges were without merit but made valid moral points.
People are kind of pathetic who miss the point they're making and take it literally only.
You might agree or disagree with their moral issue, but it's worth discussing and this does help give some visibility to another point of view on the ignored 'slavery' concern.
That's how these issues work - something is widely accepted by society, not seen as 'wrong', and some people point out a problem - take circus animal abuse, for example.
The initial response is 'that's ridiculous, those animals are entertaining and I'm sure they get great care', then whistleblowers and videos come out, and people realize there is a problem, and reforms are made, and then they say how obvious it was all along that needed to happen.
That's really not unlike the history of human slavery, which just 'wasn't seen as wrong' by so much of society, until it was.
It's quite valid to ask if there is wrong suffering involved with animals like this. If you conclude PETA is wrong, if not nuts, fine, but it's worth discussing.
We in fact do have laws against cruelty to animals that we could not have, but society has come to see animals as having some 'rights' justifying putting people in jail over.
Some other cultures might look at that and think we're like PETA, absurd, to care about animal suffering.