The dude isn't expressing himself well but I somewhat agree. It's true that the tag is accurate in the sense that there is a male protagonist in this one very specific and small portion of the game, however if somebody was searching for the 'male protagonist' tag it would be because they wanted a game specifically because they like male protagonists and therefor might not really be interested in this game?
Thus the tag can both be true, but also misleading and not terribly useful as a tool for sorting/searching for games you like.
It's similiar to any other situation. Search for 'anal sex' tag and you're going to get 50+ hour games with a single anal sex scene alongside games that are mainly focused around an anal sex fetish and one of those is infinitely more relevant to somebody searching for a specific tag.
I don't have an answer to this problem, it exists anywhere tags are used as a method of classification/sorting, but I don't think the person is entirely wrong for being misled by the tag?
That said, the more reasonable response would probably be to just go 'oh okay, it's not really a male protagonist game, guess I'll move on and find some other game' than making complaining posts in the thread or asking for games to add male protag options or w/e.