I don't see a problem with them, personally.
Adoption centres are usually ignored these days, at least from what I've seen. They seem to have lost their popularity. I guess they can be fun for it you just want to kick off a short, non-serious roleplay, although I do remember once dragging my entire pride with me from Fluorite to Bonfire so my character (the pride's queen) and her mate (the pride's king) could have cubs. I believe it was sometime back in 2012, so I'm not sure how well they work now, but the cubs stayed active in the group and were actually decent roleplayers.
Mate centres are amusing, to say the least. I've joined them, I've hosted them, I still do. Not that I'd ever actually take a mate from there or even really try to do one, but they're hilarious to watch and incredibly dumb at times. Like, jaw dropping "are you kidding me" dumb. Getting involved somehow makes it even more so. If you don't like them, block them. When I was younger I adored them because they gave me a chance to make friends and find an RP, and as a new player that was hard.
So what I'm saying is they're great for the new players and the kids, or anyone who just wants a fun, funny roleplay that probably won't last more than an hour.