It is, in the context of the events from the past few weeks. Some of his supporters had been saying for weeks now that they were "standing by" and ready to do "what had to be done" when Trump would call to them. His speech yesterday was predicably heard as the call.
I don't believe for 1 second that he didn't intended for his words to be interpreted that way.
And for the record, #KillAllWhatever should be banned as well in my book, I'm not defending it.