I mean, that’s a matter of personal opinion (and you are entitled to yours). Legality aside, I personally think some groups should have special protections as they are often targets of discrimination or harassment specifically because of their affiliation with a certain group. That includes race/ethnicity, religion, sexuality, gender identity etc.
Of course, these people are also individually protected from harassment and discrimination through other laws as you say, but the incitement law protects them as a group and from being targeted in certain ways. You are allowed to publicly protest against Judaism, but not to publicly wear swastikas (a symbol of the horror of the Holocaust).