It makes no lasting difference to the world if Team A wins against Team B in a sports event.
But public policy choices are absolutely fundamental to personal opportunity, personal safety, quality of life, and financial stability.
There are objectively right and wrong answers in politics. There's also a hierarchy of importance in policy, with some issues making far more of a difference to all of the above than others.
Misunderstanding policy cause and effect and picking and promoting the wrong answers will lead to objectively bad outcomes for at least some other people, and very probably for you personally.
The toxicity doesn't originate in social media. Social media simply amplifies the toxic effects of industries of dishonesty - from PR, astroturfing, and manipulated academic and media narratives, to calculated and deliberate hostile attempts to focus conversations on low-impact but high-emotion issues, and to split populations along tribal and narrative fault lines.