You curate how you want your account to go on any of these sites. Twitter is where I follow more news and science folks; Instagram is a photo and video sharing site and I share garden, pet, topical stuff that is generally less political than other sites. It depends on what accounts you choose to follow, what content you see.* But right now it's difficult to choose who to follow on Twitter because the authentication activity has been trashed. Start small with known sites and look to see who they follow and build that way. A search on a name is bound to get disparate results and you may find yourself in the tall grass very quickly.

*I take a look at who is following me - and if they're spammers or scammers I block them.