As far as I'm aware Keith Van Horn never made a public statement that I wasn't actually him. Even when I eventually went to BYU and became a BYU fan and said good things about BYU.
I could list my name as BarryO and let people assume I'm Obama and I don't think the argument "well Obama never said it wasn't him" would hold sway
Beyond that, what do you want? Another anonymous account here to say "that's not Alema! I'm the real Alema"
Or should he call a press conference and announce live that it's come to his attention that a cougarboarder has used a name reminiscent of his and he would like to clarify that it is not him.
More than likely the only people who really need to know (Zach Wilson, Kalani, Whittingham, Beck, Jaren Hall) already know he's not actively trashing them on social media