For starters, I'm not so insecure in my masculinity to feel insulted by an animal being bigger than me. That's like feeling insulted by a horse having a bigger dick than you... of course it does, it's a horse. Not a reasonable comparison. The MC is big for a person and that carries a totally different meaning than an animal which is just naturally big.
That has nothing to do with the point being made lol. read again is pretty obvious that it isn't about "feeling insulted" more that it is more of an insult than a compliment given the context. (context means everything).
Secondly, again she does that before getting with you. Not to get too weird about it because she's a fictional character but it's pretty unfair to feel jealous of a partner someone had before you even expressed interest in them.
and again go back and read my points, I have addressed this point many times already. And won't be a cracked record.
And lastly, again, the MC is not you. I don't know how many people self insert to the degree that they feel that a character with a predetermined personality, build, etc somehow represents them, but I know I don't. The sister could literally make fun of the MC's dick and while I would think it's rude(and not sexy) it wouldn't make me jealous, because she would be making fun of this fantasy town guard shmuck, not me.
.... are you.... are you serious? Is the concept of immersion out of your grasp?
Is game design 101 that the player will likely self insert on your protag if you have one. because of this magical thing called immersion.
Just because you yourself don't understand immersion doesn't mean it suddenly doesn't exist.
People self-insert all the time, is why certain games get so massive popular *cough* witcher *cough*
You seem to be using your own personal experience as the be all end all for all experiences. which well is flat out wrong.
But... broken record time (yeah I said I wouldn't do it... but fuck it, I will make an exception for this point)
here are some simple facts that you need to acknowledge before you can really make any argument worth reading:
People self-insert, they like to self-insert, living another life in a fantasy setting and such is fun, we also have a fancy word for this called escapism (healthy in small doses).
To use a famous person to back up that sentiment and using the game I gave as an example, Henry Cavill, and the witcher, he himself has stated that playing the game is like living another life, and that acting the character is like playing another run of the game.
Immersion is a thing, some may not self-insert directly, but they can still get immersed and care how a character is treated.
And finally.... just cause you feel and think a certain way... doesn't mean everyone does. So don't treat your own experience as the only experience.