At the risk of sounding tin-foily...
Twitter's financials for server costs have never made sense - the amount of money required to serve the sheer volume of engagement can't possibly have been resolved by ads that Elon is somehow refusing to keep tapping into.
I'd wager that some other interested party engaged in some type of private-public partnership was floating costs for (let's call it "privileged") access to the backend of Twitter -- granting a bottomless pit of funding to keep the platform running no matter the cost.
Once Twitter left the hands of someone deemed trustworthy, that life support doesn't stick around -- leaving Twitter facing complete insolvency by October of this year unless Musk literally does whatever he can to reduce engagement to save on costs.
Twitter loses more money when it has more engagement. If you have 100k users and add a new one, every interaction that additional user makes with tweets viewed by those 100k existing users requires 100k updates pushed to those 100k users' pages. Every like sends an update of +1 like on the tweet to every one of the 100k users. It becomes significantly more expensive per user engagement.
The ads being seen by additional users don't cover that constantly-compounding cost to keep engagements up to date across the platform. Musk isn't being honest about the reasoning (web scraping issues my ass) and is scrambling to buy desperately-needed to keep the platform up past October.
I think this goes to show just how impossible a business model like Twitter's was from the jump and shines a light on the absurdity of it being self-sustaining without a massive source of reliable external funding.
Edit: fixed typo
Quick side note: you are within your rights to refuse service based on political affiliation full stop -- it's not protected under the equal protections clause.
That being said, the issue is not about denying service full-stop, but the right to refuse expression of values you find to be wrong. Believe it or not, these cases are important for everyone and guarantees that the state can't force you to create messaging in support of (i.e. endorse, which is a form of speech) something you disagree with.
It's not granting the right to discriminate. It's protecting your first amendment right to not be compelled to engage in speech you disagree with.
For example, say I go to a bakery run by devout Muslims and request a cake that depicts a cross with the phrase "only through Jesus may you find eternal life" underneath. That baker may be uncomfortable with the idea of creating that design as it not only goes against their own sincerely held beliefs, but may conflict with some negative views they may hold of Christians or Jesus (or even the particular denomination of the customer).
That Muslim baker has every right to refuse the design of the cake on free speech grounds. Religion is a protected class in the equal protections clause, so the Christian may feel like they're being discriminated against, but it's the message (which is considered to be speech) and not the individual being a Christian causing the issue.
That Muslim baker cannot blanket-refuse any Christians from buying any cakes. If that Christian customer instead asks for a blank cake that they'll decorate themselves, the baker must sell it to them or else they are violating the equal protections clause. In that case, service is being refused based on the traits of the customer rather than on the particular message being expressed on the cake.
It's silly and I think people would be better off just accepting the work and taking the money. If I was aware of a business that made cakes, websites, whatever -- but refused certain designs based on their personal views, I would simply discontinue any further support of them. I'd prefer a business who puts their own shit aside and serves whomever wants to pay them.. but to compel them to suck it up and either compromise on their views or close up shop is directly contradictory to one of the most important rights we recognize here -- to speak freely and without cohersion from the state.
The business owner isn't doing anything wrong with their signs, but they're completely missing the point of the decision and comes off as a bit silly.