I think it depends on the show, really.
For example, my comic is comedy-based and pertains mostly to stuff from my own life for content, but sometimes a scenario comes up that shouldn't happen in real life (burning my house down cause of a spider, having a conversation with a glitchy, inverted version of my avatar that represents anxiety), in fact, my avatar is a 'Slimefolk', or a slime that evolved to take humanoid shape (this isn't explained yet in 'canon', it's just how I look.)
Why am I able to have a conversation with anxiety personified? Why can a version of myself come back from an alternate future and tell me to go to sleep? It doesn't matter. It's just there to serve a punchline.
Now, of course, if this is about a cartoon where the world-building does matter (I.e. Steven Universe). then it's different, and plot holes should be taken care of.
No matter what though, calling it 'just a cartoon' is simply the wrong approach, even if it's true. To some people it can even come close to an insult, suggesting that it doesn't matter or need to be held to the same standard as other mediums of story-telling simply because it's animated.