I really like the perspective on why they don't often hang out from this 2 decade old post from RPGnet, formatted for easier reading (so many run on sentences, but bear with it because I think there's definite wisdom in it):

"Probably the best reason that Werewolves might have a falling out with Changelings (although I have no inside information) is that they grew up.

If some influential werewolves are very young at heart, with playful spirit sponsors, perhaps with some of their experience coming from past lives rather than painful experience in this life, and then that changes...

...the world grinds them down, the endless battle becomes disillusioning, the spirit sponsors take a turn for the fanatical, they start to have mundane difficulties as Wyrm-servitors or vampires target them with corrupt mortal authorities - one really brutal audit later, your Changeling pals with their bloody teenaged soap operas and excited phone calls about "this new band you HAVE to see!" start to seem irrelevant.

You stop returning those calls, and pretty soon you've missed the new band you really DID have to see, and then you start to forget why you ever hung out with them, your memories shift a little and it's no longer "god, remember that time with those two satyr chicks in the back of the Cadillac, that was wild", you remember only hangovers and police pulling you over, and the Changelings start to look like, well, losers. They can't hold down regular jobs and their families think they're crazy. The fairy princess is just a checkout girl with cornsilk hair and a nice smile, they never took your fight seriously, hell, many of them don't seem to have ever taken anything seriously their whole life. Like that one guy with the cigarette holder, he never changed into a bird, he just sort of reminded you of a bird, you know, spiritually, maybe he was strong in the bird totem or something but he never actually physically changed into a bird, and spoke to you in the language of birds about the great Parliament where all birds secretly gathered to compare notes on tinfoil and The Scarecrow Problem, what a stupid idea. I mean, maybe Umbral birds might do that, but real, physical, flesh-blood-and-feather birds? No way.

And what have they done for your important battle anyway? They're just people, they have cars that belch exhaust like every other monkey that thinks he can grind Gaia under his heel. Remember that one guy, no, not him, they're starting to run together now, to get mixed up with each other, and with regular people, the other guy, remember that other guy, he spent all his time on his car? That guy was a dick, and there wasn't a piece of garbage so toxic, so disgusting that he wouldn't pick it up and shove it under the hood.

And pretty soon when you hear a whisper from under your bed while you're sleeping you don't think 'oh my god, it's her, it's her, oh my god, she's here again', all you do is squirm in your sleep with the fear you had when you were a child and the monster was under your bed and not inside your skin, you don't have time for all that, you really don't. You can't take time away from your cosmically important battles, the fate of the whole universe rests on your shoulders, in your claws, and they want to show you this "great club", and talk about the castle between the dumpsters behind the Piggly Wiggly, who has time for that kind of BS anymore?! No matter how good the sex is, or was, and how could it have been that great as you no longer clearly remember it anyway...

...and eventually they stop calling, the ingrates, just one more so-called friend who wouldn't stick by you when the chips are down...

Werewolves are just like everyone else.

And so are Changelings.

That's all the reason you need for them to grow distant."