One can hold different opinions about Stewart's day to day views of contemporary F1 matters. He sometimes takes positions that I do not agree with. But there should not be a question that he has a place in the paddock based on his achievements and character.
To drive a death trap F1 car of the sixties at competitive speed on the Nordschleife or Spa was dicing with the devil and took some brass balls. Making it a tripple champion in F1 is something special in itself and should be respected. There are only three drivers in F1 history who won more championships. Nobody can deny that Stewart was a great talent of his era and he outranks hundreds and thousands of racing drivers with lesser achievements.
Others have already mentioned Stewart as the first champion and F1 personality who kicked off modern safety standards and organized the drivers. This took perhaps even more courage and could have only been done by a man who stands by his principles.
Stewart is dyslexic and not the trained PR type you expect from modern drivers but he knows a great deal more about the sport than most people posting on this board, I bet.
All the champions of the past have paddock access and are invited to share their views with the public. I think that is a very good institution. If we criticise a personality like Stewart we should do this in a balanced way which I feel is not what the OP did. It falls back on him.