What message(s) did you take away from this movie?

Was this movie teaching something?

I assumed Martin was going to cause a lot more trouble than he ever did, and perhaps that was part of Sebastian's error, how he realized too late, that the poor kid just wanted to be close to Sebastian.

Martin lied to get his way in. When the plan went awry and his parents caused trouble, Martin waited near Sebastian's car to attempt again to see him again. That was not a good reason for Sebastian to hit him.

There is a stigma about same-sex affection. Maybe Sebastian was alarmed that another male was potentially attracted to him and was definitely worried what the school and the neighbors might think.

Perhaps when Martin was gone, Sebastian realized how Martin was innocent and how Sebastian could have handled him so differently. Martin was only guilty of infatuation with Sebastian, and so in the end Sebastian realized the good in that, instead of something bad. But it was too late.