In addition, Gary is one of the league leaders in % of times being chipped. At one point earlier in the season he was 3rd in the NFL. That's going to affect sacks, pressures, pass block win rate, etc. If you're 3rd in the NFL in % chipped, the league knows you are pretty darned good. Gary is also excellent in run defense and does a great job of setting the edge.
Yes, the Pro Bowl is based a lot on reputation, but usually it's earned. 2/3rds of the vote comes from players and coaches, and they know who is good.