Why is everyone saying this? First of all, they're completely different types of player, making direct comparison less than straightforward.
Secondly, I don't think there's anything obvious about it at all. Why do people think Salah is so obviously better? As an all round player? Come on.
Fair enough if people think Salah is better, but whether he is or not is extremely debatable IMO.
I'm far from a Liverpool or Gerrard fan, but I think he's being a bit disrespected here.
You could also ask why anyone would consider Gerrard a better player than Salah? I'd say Gerrard is a worse version of de Bruyne and Salah is on the same level as KdB, IMO.