Trump specifically said the proud boys should “stand back and stand by” during the presidential debates when asked to disavow their actions. They were also in direct contact with Roger Stone, one of Trump’s decade long advisors. There is video of them on Jan 6 with Stone, talking with him and “providing security.” They then led the charge into the capitol, breaching the building and riling up his supporters to do exactly what Trump wanted that day, create havoc to prevent the democratic turnover of power.
The proud boys and Trump’s camp were tied at the hip, coordinating with each other. It wasn’t a “happy accident” that they kept showing up for Trumps bullshit.