Is it best because a user making a legitimate parody or review is likely to get a strike on their account because the automated ContentID system cannot tell the difference between a straight copy and what ought to be fair use?
Is it best because hateful crazies can get your account closed with a flood of phony copyright complaints?
I can get a diploma in Zerg showing I can drone hard? Awesome...
*Reads submission again*... oooh. That kind of drones. That's a lot less awesome.
That's a fixable problem. For example, you could read this article by phk in ACM: https://queue.acm.org/detail.cfm?id=2030258
In particular note:
Clause 1. If you deliver software with complete and buildable source code and a license that allows disabling any functionality or code by the licensee, then your liability is limited to a refund.