The protest could have continued to be disrupted the way they already were before the massacre:

Through wiretaps and arrests Through planted dissenters sowing chaos in the student’s ranks Through rubber bullets + tear gas, and other nonlethal methods

A) There was no "massacre"

B) We have no idea if these tactics weren't also used, and

C) Let's be honest, if they had done these things and it had worked, you people would never shut the fuck up about that either.