"The Alt Right will aggressively disrupt the left" ?
Corporations, the media they own, the politicians they own, and the shills/trolls they fund have already "aggressively disrupted the left" for decades.
Ever since the 1985 formation of the Democratic Leadership Council (DLC) the Democratic Party has no effect at the federal level except to elect Republicans and implement Republican programs better than Republicans could.
The percentage of US voters identifying as Democrats has been in decline since 1960 with the steepest declines occurring at the end of Bill Clinton's and Obama's first terms. The percentage of US voters identifying as Greens has been increasing ever since Bill Clinton was elected in 1992.
Which Party is on the right side of history ?