Because he shouts out LA/Compton all the time and any time there is something big with LA/Compton he never seems to get an invite.
In part he should have been there, maybe he didn't get an invite or maybe he declined who knows.
That shyt eats at his soul. His reaction to missing out on the superbowl was an insight into it. This one, though not as big mainstream wise - has more value culturally.
It's literally a watershed moment for Hip-Hop and LA especially. I very much doubt he would have skipped/declined an invite. I know he's cool with Drake, but plenty people that are cool with him were there. This was a moment LA/West Coast were putting on for the world to see. Ties, culture, bonds > artificial popularity. Like, some of the people on that stage rep sets that are/were mortal enemies.
The more likely explanation is that he didn't get an invitation due to his ways, and who he decided to pledge allegiance to (Drake). Son backed the wrong horse