You can't feed in a court exercising family law jurisdiction because nobody under the age of 18 is allowed in court (unless they are a party to the proceedings, ie a parent of a child but they are still under 18 themselves). Bit difficult to feed if they're not in the room.

Any other court should be fine. Some consider it disrespectful, like feeding in church or at a wedding mass, but given there's no law against it....

I think it would be ok if you were an observer, but if you were the accused or a party in a case that was running, the judge may consider that you are unable to effectively participate in the proceedings whilst you were feeding, and would thus adjourn the court. You need to be fully on the ball when you are a party to proceedings, missing even one word can change the entire case. It would be more about having your full attention on the case rather than some form of discrimination IMHO. The judge would be looking after your interests if the court were adjourned to allow you to feed.