1. It takes 4 of the 9 Justices to vote to take up a case. Given the current 6-3 split this likely means the conservative supermajrority voted to take the case. Why they then chose to dismiss it we can only speculate about;
2. The Supreme Court consistently sides with big business and this has likely been the case since its inception. This isn't strictly true but tends to be a good predictor of what cases the court takes and how it will rule;
3. SCOTUS is and always has been political. Supreme Court justices are political operatives;
4. This court will be inclined to side against Big Tech in general and social media in paritcular because of the war on the (implied right of) privacy and the pervasive myth that conservative voices are somehow being censored or silenced, despite lots of evidence that conservative rage-bait gets disproprotionately more distribution on recommendation algorithms.
One final piece of context regards the consequences of misuse of user data by the likes of Cambridge Analytica. Coming up soon is the potential ban of Tiktok. One argument for this is the influence of the Chinese government.
What you don't hear--from either party--is pushing for comprehensive user data protection legislation. So don't let any politican (of either party) tell you data privacy and protection is important to them. It is not. Or they would've done something about it.