I think that at least some of those people involved in breaching security at the Capitol, (mistakenly) believed that they wouldn't be held legally culpable for their actions because of things they had heard Trump say during the rally. Those people believed that Trump would be sympathetic to them, and in turn, they (mistakenly) believed that he would grant pardons to anyone charged with a crime that day. Trump's video calling the rioters "special" and telling them "We love you", only served to reinforce these beliefs. Basically, those people thought Trump had their backs... and they were immune from prosecution for their actions that day.