Just to cause trouble.
Not a very friendly thing to do.
Even so, AFAIK those were the only two rallies the Ruskies organized. The rest amounted to buying some online ads and internet trolling. And those two rallies were barely noticed at the time and paled in comparison, both in numbers and in terms of ‘chaos,’ to all the rallies, protests and riots around the nation organized by Americans.
Pretty weenie!
And now foreign nations have cause to start issuing indictments on Americans, justified or not, to mess with the U.S. Way to go, Mueller!