The short answer: you wouldnt
Now that Deathbellow Warcry is no longer in chests, expect its price to rise
I get that they wanted to avoid reminder text to keep these specially-skinned cards looking as pretty as possible, but if that was their goal, perhaps they should have included cards that wouldnt normally need reminder text to begin with
In addition, battlefield sweepers such as Damnation, Toxic Deluge, and their ilk also have no issue killing an entire battlefield full of protection from black creatures dead
Otherwise, you can just wipe the board clean completely
The heartfelt quote on the card encourages welcoming new players into the MTG game, making it a unique and sentimental piece of Magic the Gathering history