Why all the hate on Mods?

I realize this thread will probably be shut down but I am only curious why mods are met with such aggression. Serious answers would be appreciated.

For:
They show what is possible with the tools already provided and expand the possibilities of gameplay. Examples, you can fly a pelican, you play as a grunt, and you can build on forge beyond the budget limit.
Most mods are for gameplay in custom games only. They don’t affect matchmaking.
The community can show their input for what they would like to see in future installments. I believe Bethesda releases a modding kit with their games and many of the ideas spawned from Oblivion mods ended up in Skyrim. (Or so I’ve been told by people who don’t have any credibility)

Against:
Most mods are not well done and just have clones everywhere.
People can mod their profiles, and create unbalance in matchmaking before being banned? (Just guessing on this one)
It goes against the artist’s vision of the game.

I am not a modder by any means (I don’t have the computer skills for that), I’ve only seen Youtube videos and I like what they’ve done but we can’t talk about it and I don’t know why. I’m sure I will get a waypoint MODerator posting a generic “You cannot talk about MODS” comment and this thread locked or removed, but I am seriously just trying to understand WHY.