For the curious, the terms are here: https://man.sr.ht/terms.md#permissible-use
And even if you agree with the current set of restrictions, are you sure it will not be further expanded? I am not.
For the same reason GitHub does? GitHub's AUP at https://docs.github.com/en/site-policy/acceptable-use-polici... says:
"We do not allow content or activity on GitHub that: ... is sexually obscene or relates to sexual exploitation or abuse, including of minors".
Atlassian's AUP at https://www.atlassian.com/legal/acceptable-use-policy says "Inappropriate content" includes "Posting, uploading, sharing, submitting, or otherwise providing content that ... Is deceptive, fraudulent, illegal, obscene, defamatory, libelous, threatening, harmful to minors, pornographic (including child pornography, which we will remove and report to law enforcement, including the National Center for Missing and Exploited Children), indecent, harassing, hateful"?
GitLab's AUP at https://handbook.gitlab.com/handbook/legal/acceptable-use-po... says "unacceptable use of our services [which] applies to all users of all GitLab services including those on the Free, Premium, and Ultimate GitLab tiers" mean "you must not: Create, upload, submit, execute, transmit, or host anything that ... is vulgar, obscene, or pornographic, or gratuitously depicts or glorifies violence."
Now, there are differences between "explicit sexual content", "sexually obscene" and "pornographic", but if you are worried about possible further expansion, you shouldn't use any of these code hosting services.
A simple Google search on the topic should be educational.
Instead, I was pointing out that since all the providers I looked at have essentially the same restriction, you likely shouldn't use any of them. Certainly there are a lot of people who use GitHub despite having no guarantee the ToS won't be more restrictive in the future.
Sourcehut's ToS is certainly not exceptional in that regard, so really you are objecting to essentially every 3rd party code hosting provider, yes?
Or is there one you had in mind where you aren't concerned about further expansion?
On an account that you pay _Drew_ for. Do you also complain because someone renting you a garage doesn't want you running a strip club out of there?
As for banning sex content on a paid service, you'll find it's more common than you think, since payment processors tend to drop customers who permit that sort of thing. Porn-enabled services have chargeback and failed-charge rates orders of magnitude higher than services which forbid them.
There are a ton of reason to fire a client. The two mentioned here are completely uncontroversial from a business standpoint.