Are humans a strong or weak RNG? [duplicate]

This question already has an answer here:

• Can the human brain generate cryptographically secure random numbers? 2 answers

Thomas Pornin has stated in the past on multiple occasions (I'm not going to source them, he can argue with me if he wants) that humans are bad RNGs.

While I agree that human RNG for password generation in the mind is abysmal usually, I wanted to ask if human-aided RNG by a computer is equally as bad. KeePass has a feature where you seed the RNG by moving the mouse for a while, and while I know that if KeePass is using /dev/urandom it's more or less secure enough, I've used the mouse-seeded RNG in the past.

I've always thought that RNG aided by human input would be better than just standard PRNG as provided by an operating system. How could someone predict exactly how I'd move my mouse, at what rate, how often I'm pausing, etc.?