Sorry to say, whilst I agree with most of what you say (& particularly empathise with the use of irrelevant tests to ascertain suitability for a job you are already performing) I have to disagree with your assertion that there should be no limit to the number of times one applies.
There is an airline (actually a group of airlines) in Europe (TUI) that will not accept an application for a short-term contract job ,even a 2nd time, if you previously failed the assessment. Given that anyone can have a bad day, I find this a little unfortunate, as I am sure they lose many potentially worthy candidates, but, as we say, "it is their trainset" , so what to do?
Whilst I find this a bit OTT, I would tend to disagree that you should be able to keep going back, as frequently /soon as you like to be re-assessed. If they, for reasons they are under no compunction to reveal to you, decide they don't want you, unless their requirements have changed, or their only bugbear was your lack of experience, which you have significantly increased, why should they continue to re-assess you ad infinitum,? & even if they do, why do you think the result should be any different ? because you get better at doing their "tests" ? Perhaps ones ability to perform the tests (ridiculous as some of them may be) may be enhanced after a few tries, isn't that something, they justifiably , perhaps wish to avoid ?
One should not confuse owns own desires for a particular position, with the fairness of the mechanism required to obtain it.