Play a man or a teenage guy as the main character
What is a male protagonist game?
In sex games it's very common to have main characters that you can identify to. In some cases that means that the hero will be a man and that's what a male protagonist game is all about. It's a purely personal preference and sometimes you will encounter games that propose you to play either a male or a female character.
Be the man of the game or follow the main character
Playing a male protagonist game doesn't always mean that you will act as the main character of the game, it can also be that the hero is a man with its own backstory and you get to follow him in his journey. But in most popular visual novels and porn games, and despite providing you with an existing backstory, you will often be asked your name so that you can become the main character and this feeling in reinforced when you get to make choices through the game.
Imposing a gender for the main character is just fine
I could see why people would complain that a porn game does not offer the option to have either a male or a female protagonist. But if you think about the way a story is written, proposing both would complicate a lot of things. The relationship between the characters might differ, the lifestyle and friends, and in case that it would be a hentai game in a school environment, you can imagine that starting the game with a male or a female character would drastically change the day at school.
We're always happy to see games proposing both options such as Cloud Meadow or 3DXChat, but we also understand that adult gaming is mainly dedicated to a male audience so most of the games available usually have a man as the main character.
Hentai games with male protagonists
Japanese porn games for men are very popular
It's not really a surprise that hentai Japanese games are mainly resolving around male protagonist. After all, the adult business in Japan is mainly dedicated to men. The good thing is, the variety and quality of hentai games is great! You'll often find yourself in situation with multiple girls to romance (and to fuck) and there will always be a hint of jealousy. Obviously it's not the only type of stories or games you'll find but they account for a good amount.