I had to Google it because I thought I was McLosing it.
Mayonnaise is a dairy-free product of eggs and oil mixed to create a sauce.
Some store-bought brands may contain dairy, but it's not required or possibly common.

That Twitch dot tv dot com streamer. That once FGC commentator and memer with some bangers.
On the front cover of The Lara-Su Chronicles Beginnings by Ken Penders (top-right)
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I had to Google it because I thought I was McLosing it.
Mayonnaise is a dairy-free product of eggs and oil mixed to create a sauce.
Some store-bought brands may contain dairy, but it's not required or possibly common.
Eggs were lumped together with dairy under the food pyramid/food groups (maybe just because they’re often next to each other that the grocery store?). You’re not going bonkers.
maybe they don't know what the word dairy means and they think it includes eggs?? that's the closest thing to an explanation that i can think of...
I have definitely met multiple people who think that mayo is dairy because it's something you eat that's white and creamy.
There are words in other languages that are roughly equivalent to english "dairy" but also include eggs.
So it could be the case of translation tradeoffs if the game was made outside on english speaking countries. I mean - how would you translate "milk-or-egg-based-products" into one word in that case?