So they didn't rule if the "no hats" rule should go, they were asked if such a rule - if it exists - is applicable to religious hats or if the right to religious freedom protects such symbols. So they rule on half-theoretical questions that are often narrower than the case itself.
And I find that very structure harmful. Because by formulating the question asked of the court in a specific way, then limiting the answers it can give to only that question, you can force these kinds of discriminatory judgements while pretending that that wasn't the point.
The court should be able to say, as part of the ruling, that while exemptions should not be given on religious grounds, justification for rules that are considered to infringe on religious freedoms may be asked for.
We can easily give a reason why discrimination should not be allowed while serving the public, and similarly why antlers cannot be worn in a workshop.
The "no hats" rule in this case wasn't a "no hats" rule, but a "no religious symbols are allowed to be worn by anybody" rule. The court saw such a rule as justified because it did not discriminate against specific religions or symbols.
Which is ridiculous because a hypothetical religion could use pants as a symbol of their faith and suddenly pants are banned.