Applying the Insurrection Act in this case is much more dubious, legally speaking, than it might seem. The protests are not in opposition to the Federal government, and the Department of Defense reports that there are 0 requests from state governments declaring them an insurrection against the state and asking the Feds to intervene. That's two of the three legal justifications blown out of the water. The third justification, that of resolving disorder that is preventing exercise of civil rights, would probably not stand up in court unless it was used against the police (who bear the primary responsibility for this getting out of hand, because they vastly overreacted to the well-justified protests), not for them.
Given that any orders to do anything would have to go through career officials who very much do not want to be the star guests at capital trials in a few years, any actual use of military force is highly unlikely, except possibly in an unarmed "physically separate them with sheer numbers" way.
Except that the exercise of civil rights is not the be all, end all of section 333. In relevant part:
"The President, by using the militia or the armed forces, or both, or by any other means, shall take such measures as he considers necessary to suppress, in a State, any
. . . domestic violence . . . if it--
(1) so hinders the execution of the laws of that State, and of the United States within the State . . ." 10 USC 333.