Freedom of transaction is not a basic human right - there are some markets so abhorrent that the correct response is to imprison those who participate in them.
Like, absolute freedom of transaction means that you could participate in assassination markets. It'd even be structured in a way that the buyer could avoid paying for performance - simply make a large payment available for whoever happens to accurately predict the day of death for a certain individual (and make the predictions expensive enough that you basically have to kill them in order for it to be a good idea).
A slightly more narrower statement of Freedom of transaction would be "if you can do it for free, you may do it for money".
Assassination is illegal by itself, paid or not, so using it as an example just confuses the issue. It's like saying Freedom of Speech is not a basic human right because you can use speech to order someone to be killed.
Like, absolute freedom of transaction means that you could participate in assassination markets. It'd even be structured in a way that the buyer could avoid paying for performance - simply make a large payment available for whoever happens to accurately predict the day of death for a certain individual (and make the predictions expensive enough that you basically have to kill them in order for it to be a good idea).