A politician has a Constitutional right to to be a vocal advocate of a nonlegislative boycott.
U-bet.
To the same extent that a local crime lord has the Constitutional right to publicly say "You know that FreeReign character? The world would be a better place if he was dead, you know what I mean?".
I know New Jersey RAT politicians are pretty sleazy, but I'll ask you this?
If the local crime lord said "that the world would be a better place if the doofus SauronOfMorder were dead, you know what I mean", you would equate the risk of bad intentions from that remark similar to the risk of bad intentions if (let's say) a local politician solicited you and your business on the phone for a campaign contribution??
And similarly, Freepers have the Constitutional right to respond to such utterances with calls for the the politician's censure and/or removal from office.