Free speech is a two-way street, and boycotts are a form of free speech.
Now remember, boycotts are different from the govt. controlling businesses.
So you would boycott a cell phone company for letting a group send messages to people who signed up to receive those messages? I’m going to go out on a limb and say that there are plenty of messages sent over the Verizon network you do not approve of. Especially with the advent of media messages and sending video.
Will you boycott Verizon when they don’t allow pro-life groups to send messages either?
And free speech is also about allowing messages you do not approve of to be sent. In fact that is the primary purpose of free speech.