Warren was effectively silenced because turtle-neck McConnell thought this was a violation of the rules:
Under the Senate's ”Rule 19," senators are not allowed to ”directly or indirectly, by any form of words impute to another Senator or to other Senators any conduct or motive unworthy or unbecoming a Senator."
Hmm... if that is the rule, I don't see how it was not applied correctly. It says directly or indirectly. I'm a big fan of Elizabeth Warren, but it sounds like they are using the rule as intended.
Then again, I have very little experience in Senate Rules.