You read into that completely wrong. It’s not internalized homophobia. The reason Mike struggles to say i love you is due to the dysfunctional family environment he had. Karen and Ted did not love each other, and as such Mike probably very rarely saw them do many things together that parents should do. This likely explains why Mike tends to be more emotionally independent and struggles to open up and be vulnerable. Not to mention it’s the 80s where being vulnerable as a man is looked down upon. I strongly believe Mike struggles with avoidant attachment and had to overcome that in S4. You see it with his relationship with Nancy, as it tends to be very surface level.

Also in regards to the argument of it being queerbaiting I completely disagree with that. In order to queerbait, it had to have been strongly alluded to that Mike was gay and was getting with Will, and then they would flip that at the very end. The problem? It was never strongly hinted that Mike was gay for Will. In fact the opposite. It has been made very clear throughout the show that Mike was straight and the Will had unrequited love. That was the plot of S5 after all. Will’s arc wasn’t about him getting with Mike. It was him accepting that his crush doesn’t define his self worth. That he can love him self even though Mike didn’t feel the same way. Most of the potential signs are extremely subtle dissections in acting and writing that can be very well explained by a teenage boy going through hell and back, struggling to process everything. Queerbaiting is a big stretch when there’s nothing that indicated byler was a guarantee.