No it isn't…..big difference between not liking nettle stings and then wearing shin pads, which might be described as overkill for a lot of riding, and someone who would die eating peanuts.
Not everyone dies from eating peanuts…..that is taking it to the extreme, but plenty still get a swollen throat & itchy mouth, whereas I suspect you do not – similar to your lesser reaction to nettles than the reaction I get.
And yes, I do take an antihistamine before riding and it does help a bit but doesn't stop it completely. The resulting stings still last about a week, it's just they aren't as swollen/itchy initially…..
I agree that wearing shin pads is not strictly necessary to do the job, as trousers/leggings/football socks would also work. But shin pads allow some airflow to the back of your legs and are convenient. As I mentioned above, I will probably try some football socks if I ever remember to buy some….