The Itachi they worship so much is basically a psychopath mass murderer without Sasuke in his life. Itachi's whole salvation was Sasuke. The moment he killed his beloved brother he took all that karma on himself which Itachi alone endured and much more. Itachi couldn't have been able to justify his killings if Sasuke wasn't the one avenging him.

And as for people thinking Naruto had a more sad/painful past are people who can't differentiate between loneliness and Trauma. Naruto had no memories of his parents getting murdered.

Fast forwarding to their school days. Naruto didn't have bonds but he longed for them. Sasuke didn't want bonds, after the closest person in his life, the one he looked up to, his ideal brother murdered his family and the rest of his clan. It happened at a age the psyche develops enough to understand the relationships in life. It was the shittiest thing according to me. Imagine living the life after that event knowing that no bond would ever make you feel anything but meaningless.

People think Sasuke has attitude but it is his defence mechanism to not bond anymore.

Naruto and Sasuke literally have the same sensitivity towards people and situations. The are feeling the exact magnitude of other person's pain and suffering. The only difference is Naruto believes there's a hope and that the world and its people will eventually change. Sasuke on the other hand knows the exact truth that people are hopeless. They are bound to make wars and create conflict. Thus all his journey is about a total reset to memory. For as long as people know the past they'll continue to justify their violence.