Because he marched with MLK, John Lewis knows he's got built in immunity for life from criticism. He uses it to cash in as a corporate whore.
Fucking racebaiting pricks. It wouldn't matter how tame or limp the criticism of Lewis (or any minority for that matter) was, there would still be trolls calling it racist/sexist/bigoted.
In my opinion the Democrats trot out John Lewis on occasions when they simply need a tool, like Republicans used Colin Powell.