It’s not a pun:
https://en.m.wikipedia.org/wiki/Pun
It’s more creative than the usual one that translates to “something you find in the catbox”, though. I’ll give it that.
It’s rather insulting to dedicated family members who lovingly care for ill or elderly loved ones, though, and those suffering from medical conditions that require catheterization. I don’t mind it for my own sake — what’s another childish insult to me? I just consider the source. I do find it distasteful on their account, however.
Given that the social media poster CatTurd seems to be at least ideologially neutral towards Q, I wasn't going to give you false credit by making that connection.
As far as the pun, as you have been giving off airs of virtue-by-association with the medical community, and catheters are a medical device, it was a very nice pun.
Get rekt, troll.
Spoken like a true liberal. Raise your eyebrows a bit higher and maybe you can achieve unpowered flight.