Hey there. I'm not the creator of this game, but I am a hobbyist creator in my spare time. I just want to let you know that giving unsolicited advice is generally NOT considered good practice, especially when it comes to indie games that are made in the creator's free time and pure love.
If you feel like the dialogue is too blunt, you could have expressed your opinion and left it at that, but you really don't need to bring up "recommended lessons" or "studies" on how to do things "right", especially if you don't know whether the creator intended whatever it was that you didn't like.
Also, it ABSOLUTELY isn't good practice to bring up the work of other creators in the comment. It's one thing if you know the two creators are friends, but usually, such mentions just end up being awkward for both parties.
Whether or not it's appropriate to call a stranger "cute" will not be my judgment to make, as different creators have different standards when it comes to boundaries with their audience.
I hope this doesn't come off as scolding or anything. I'm sure you mean well and that you genuinely believe you're helping, but good intentions do not justify the repercussions of your words. There are those who truly want to learn to "write better" and there are those who simply want to share their stories with the world. There are objective standards by which writing can be judged, such as grammar, and there are creative choices that are entirely a matter of preference, such as the "bluntness" of dialogue and how "straightforward" a character should be.