Immigration is obviously an incredibly complex concept -- full of emotion, stats, and created realities -- and polls can be used to make arguments for nearly any position. So while I won't try to say, one way or the other, whether a good number of Americans support what the Minutemen are doing, they are certainly not universally beloved.
But those people who decided that their contribution to "free speech" was to storm a stage and shout over this Minuteman assured, for some time, that they're position elicits no sympathy; that the Minutemen are the victims here.