businesses, especially ones operated online, can really reject you for whatever reason they want.

Legally speaking, this isn't actually true, at least in America. Businesses are not legally allowed to discriminate against protected classes. For example, it's the reason why it's illegal to refuse service to someone simply because they're black (race is a protected class) but ok to discriminate against say redheads (hair color is not a protected class).

False. It is illegal to discriminate against someone based on race, religion or sex, according to Title 2 of the 1964 Civil Rights Act.

America was at a crossroads of what freedom really meant 60 years ago, not today. It is now long-established law that freedom is the ability to shop wherever.

All that is up for debate is whether sexual orientation should be included, despite not being explicitly included. Textualists say no, intentionalists say yes.

That's true. Moving past the emotional attempt to rile up the community by stating "throw it into the fire", it isn't clearly defined what a business can refuse business for.

If someone at a restaurant acts like a complete jerk and the business rejects providing service, is the business wrong for punishing the customer for expressing their freedom of speech? As long as that customer is not trying to incite violence, as it stands, there is no clarity on which party would be in the right.