Schumer wasn't booed until began politicizing the inauguration by saying “we live in a challenging and tumultuous time.” It was a direct slam at Trump and his supporters.
Continuing down the path of doom and gloom, Schumer finally got to this: "Despite these challenges, I stand here today confident in this great country for one reason". As if on cue, someone in the crowd shouted out "TRUMP!"
Because the reason everyone was there was to see Trump sworn in as President - not to hear what bad shape we are in because of the election results.
Schumer can pound sand. He never should have been granted a microphone to begin with.