Ha? You read it up until this latest chapter and the only thing you know is about "the fan service for bl fans"? Are you dang serious? Can't you see how cute, adorable, lovely, fluffy, beautiful, amazing, extraordinary cute, super super adorable did i mentioned capital CUTE our beloved Gru is? This whole arc is a fan service of Gru's cuteness! She's serving us top tier cuteness then you only know about this one a few bubbles about "misunderstanding"? You're weird. Ma'am. So weird. Our Gru was there giving us all the glory of her cuteness! Serving us the most glorified adorableness! And you were sayin this is a fanservice for something that was only mentioned a few times and not really the main trope? Are you for dang real?!
im pretty sure this arc is where gru discovers she can be family with people that arent biologically related to her. like how she was confused why they were mistaken for a family even though they look nothing alike, but zhenya explains that family comes in different forms and you dont have to be related to be family. this is onset of gru opening up a closer, more familial relationship with the guild master and her other "parents"

Till when does this animal dungeon thingy last. It's getting boring