There is nothing wrong with being anti-American as America is a white supremacist and genocidal nation-state (and especially anti-people-like-me) and should be dissolved with land given back to Indigenous nations.
Regardless, from what I understand from friends who are supporters of Ansar Allah and are in the region is that they're made up of multiple factions and are a heterogeneous movement. Of course, I may be mistaken as the words you quoted give me pause for thought.
I do not support them, but it would be best if they stopped arms shipments and I myself want to try and block arms shipments to Israel, even if I get arrested.
As someone that is Turkish, I grew up being sympathetic to Palestine and I am definitely sympathetic now.
I haven't heard of that banner. Which one? If what you say is true, then yes, they are anti-Semitic and I'll have to rethink what I said.
But I also do not see much of a solution.
I'm also Latino and the media lied about the U.S. invasion of the Dominican Republic and the ouster of Juan Bosch (now the media lies about Palestine or carries water for Israel). America and its vassal-states keep winning; we need to fight back somehow.
Thanks for trying to make me see reason, at least. The banner's words that you quoted are atrocious, of course.