I know you're mad that you can no longer claim that Trump was exonerated or that he escaped indictment because there was a lack of evidence. Mueller explicitly said they didn't indict Trump because of the OLC memo.
Mueller has always kind of searched for the precise word he wants to use. Considering how his answers were so substantially limited by DOJ just a day before his testimony, it's fair to say that his extreme caution and quest to be precise is not something Trump sycophants are able to appreciate.
I find it a bit ironic considering Trump inserts his foot into his own mouth on a seemingly daily basis. "Many fine people on both sides" "I fired him [Comey] because of Russia" -- I could go on and on. Maybe being careful and precise is something Trump should bone up on. Besides, they're questioning a guy about a 500 page report, his ability to answer was sharply limited by DOJ less than 24 hours before his hearing (interesting that Barr waited until the last moment to respond to Mueller when he inquired about any limitations 14 days ago), and the GOP and Democrats both keep asking questions outside his purview, or that have been limited by DOJ. Anyone watching knows that both the Dems and GOP studied the DOJ letter and are craftily trying to get around it's limitations with inventive tactics and questions.
If Mueller came out and was flippant with his responses you'd be attacking him for being reckless. Mueller could save your life tomorrow and you'd still bash him on a daily basis because the god you worship is threatened by him.