There’s no way someone will forgot the most important part on this promotion to be qualified.
It’s more on intentional to censor it because the 5K wager is too high for a 5$ free bet. You will likely lose more than ten folds of that reward just to get a 5K wager even on the lowest house edge games like Plinko.
Only few will be attracted to claim that bonus if they saw immediately the requirements.
Many gambling platforms don't emphasize the wagering requirements for bonuses, and probably do so deliberately in order not to scare away gamblers. Incidentally, the Betfury site states that Plinko has an RTP of 99.02%, which means that the expected loss will be $49 when wagering $5k. With this in mind, that free bet no longer seems like such an attractive offer.