It would be better not to ask for money to participate in such promotions. That's what promotions are for. Many people actually get interested in the platform and play when they are offered a free promotion.
Maybe they'll change it. I also don't rule out that they will do another promotion in between on the forum now that the European Championships have started, and the Olympics are coming too.
There are also nice promotions to link to.
Not all promotions should be free, a casino is a business and owner should be able to manage the funds for promotions wisely. In this case, they have provided free predictor for many rounds and it is reasonable if they try to make a new promotion which is not free but they do not do it in the best way.