Reply to krk 5s Nothing under 50 Hz so I've heard. Is this true ?

So I was browsing facebook a couple minutes ago and one of the commenters said his krk 5s don't play almost nothing under 50 Hz. He has to use headphones for the bass. He makes somewhat deeper dubstep so poor fella.

But if this is true that makes them quite shit-tier monitors at least for what I would expect from them. Is adding a sub the only solution then ?

I almost got 6s but bought 1210s instead but I feel like this is something that should be known since krk is always depicted as the go to supplier of monitors. And it's good to know for the future.