Many people seem to expect "vaccinated" to mean "enjoy utter immunity to". Kinda like some World of EverDungeon video game, where having the Amulet of Foozaz makes you utterly immune to any & all poisons.
Anti-vaxer's love to play up that meme.
A better analogy would be the body armor that Marines wear in combat zones. No Marine is stupid enough to believe that wearing body armor will make him completely immune to bullets. And certainly no Marine is stupid enough to say "I won't wear it, because it doesn't make me completely immune to bullets".
Yup. And besides, it's been clear for a good while now that it boils down to personal protection and keeping hospital capacity at bay. Yet there is so much illogical fear of "antivaxxers/unvaccinated" in the vaccinated crowd.