You can like a show and not be a part of the fandom, you know!
I like a few shows that people DESPISE the fandoms of, but I don't really participate in the fandom. I watch the show, occasionally browse for decent fanworks, and that's it. I don't shove it in people's faces, or actively participate in just about any fandoms, the notable exception being the furry fandom (which, sadly, people absolutely despise)
Also, 1 year of cringe? The UNDERTALE demo came out in 2013. It's not like it only existed since its release...
And the game didn't get popular until a bit after its release anyways...
And it's not like UNDERTALE invented cringe. It's just hipsters like you who think it's cool to hate things others like that are whining about how popular it is.
"I hate bronies and undertale and furries and alphys and all the fandoms except weebs and I hate everything"
Maybe you can do someone a favor and not whine about how much you hate something unless it's relevant? I don't have a message saying "weebs are the worst" in my sig, I don't brag about disliking anything, just like I don't brag about liking it. I'd just go "I didn't like it" if asked/in a discussion post.
The exception, in this case, is FNAF. If there's one thing I can't stand, it's that. But still, I don't actively post on how much I hate it unless it's relevant to the discussion.
So, just relax a bit, alright? We get it, "all da underfail fans is cringe" but you're much better off ignoring them then whining about it.