Adhesion contracts are not limited to social media and entertainment sites, and I suspect you are picking those sites to belittle based on the frivolity those sites' categories.
Adhesion contracts appear in banking, medical, and insurance contracts and yes, when you sign up for Facebook or Netflix. Yes, you can choose different services. Please identify a banking, credit card, brokerage, doctor, and insurer that does not have lengthy contracts.
The point is that they don't have to have short contracts. If you choose to use their services, then you should review the agreements, or at least not complain when they exercise their rights under those agreements that you falsely claimed to read.
Adhesion contracts appear in banking, medical, and insurance contracts and yes, when you sign up for Facebook or Netflix. Yes, you can choose different services. Please identify a banking, credit card, brokerage, doctor, and insurer that does not have lengthy contracts.