If their establishments are open to the public, generally yes, in my opinion, within reason. And that's okay: if an entity wants to operate a business open to the public, it should be open to all the public (within reason: obviously they can't be compelled to be "open" to customers for which there is no relevant business relationship to be had). So an establishment selling only halal goods couldn't be compelled to sell non-halal goods, but it also ought not be permitted to refuse service to non-muslims.
> If their establishments are open to the public, generally yes [we need to force Muslims to sell non-halal food], in my opinion, within reason.
Either GP's question got reversed after they posted, or you misread their post, or your phrasing is off. The rest of your post suggests that Muslims should not be compelled to sell non-halal items.
I think your proposed comparison follows the headline, and the headline doesn't actually reflect the ruling.
I believe that the ruling is focused on the content, not the client. My reading is that if the same-sex couple had (for some odd reason) asked for a hetero wedding site, the web designer would not have been allowed to deny them business.
This doesn't make sense. Why would a Muslim vendor care to do that in the first place? There is nothing in their religion that says only Muslims can eat halal food. It's a completely different scenario.
> Do muslims need to be forced to sell/serve non-halal items in their establishment?
No and that is a mischaracterization of the decision. This case states that they can decide who they want to sell their items to and discriminate against those they feel are unworthy of their goods.
Decisions like this seem like tricky business, and probably doesn't help that most news about things gets filtered through two or three layers of news media first.
It's definitely a tough situation overall, and there's no totally satisfying result (which is the sign of a good case for the courts, as far as I'm concerned).
As a constrasting example, in many states, political affiliation is a protected class. If a swastika-tattooed neo-Nazi asked for a portrait, would an artist be obliged to do the painting, even if no endorsement of the ideology was requested? As distant a case as that is, it seems like the legal principles being argued here carry over more-or-less directly.