Right after knowing Alvin was much more than a Matthews, Wilson was eager to bring up their relationship and show to the world he was a progressive man and accepted a stepson.
Probably Alvin would have been happy if Wilson and Janet had accepted him when he had appeared at their door, where he lived with Janet before their marriage.
Alvin wanted to applaud the man in front of him. Was he looking like a fool? Or a kid who could be lured?
He never bothered to look into Wilson's background or get to know about him. Now he found Wilson nothing but gross.
Nevertheless, Alvin looked at Janet, to know if she was also the same kind of person. No, Janet was appalled and stood in shock looking at her husband.