I think the CLUTTERED is fair fodder for debate. I've gotten used to it, but I remember thinking much the same when I was new here.
As for DEMANDING... I disagree, and the most important reason I have for disagreeing is that WikiTree is a SHARED tree. It is not just yours. So, your personal knowledge is not a sufficient source, because it can't be verified by others.
I get that it's frustrating to have to enter all that, but here's how I've gotten around that. I initially create my trees on other platforms, and I use those while I'm gathering sources for an individual. By the time I decide to add that person to WikiTree, I have all my sources together on another platform and it's very easy to just add it all to WikiTree. Of course there are those who, no matter how much research I've done, I can never find an exact year of birth or death date - but that's OK in WikiTree too you should just explain why you made the estimate you did.
Sourcing everything can be a pain, but it's also what makes WikiTree what it is. If you don't want to source things, maybe this isn't the place for you and another genealogy site might better fit your needs.