I think that's fine and honestly ethical. There used to be a time where every game would have a demo for you to try out. Now often times you have to commit to the purchase or risk ruining the experience for yourself by watching YouTube gameplay videos.

You were right, that's an unpopular opinion.

You had a second chance.

TL;DR you did exactly what you shouldn't and exactly what was expected to happen happened... Not knowing the rules is no reason to not abide by them.