Being the protagonist doesnt mean you have to be good.
You retard, he's protagonist in this instance because he's going save his family from being enslaved and that Roger & Garp opposed him from doing that.
Oda whitewashed Xebec. He didn't show doing any evil stuff on panel for a reason. He wants us to root for him in this conflict
He's basically trying to say that Xebec isn't seen as a bad/evil guy or at least he's not meant to be, which is dumb.
Xebec is indeed a bad person, it's just that the people in the World Government are FAR worse than he is, y'know given that one of them isn't hosting events every three years where they hunt "rabbits".
We're meant to root for Xebec in the same way we're meant to root for Bege in WCI or Kidd in Wano. They're still scumbags, but they're up against far worse scumbags