I'm sorry but this isn't just a social media thing at all. Tifo have even done a video which explains it well.
I know people think that shot-stopping is the most important thing a goalkeeper does but even if that is true, which is quite debatable in a dominant team facing less and less shots, his shot stopping is only measuring out at average this season. Given he's arguably the worst keeper in the premiership, and certainly among top clubs, in the other gk areas, (sweeping, claiming high crosses, playing out from the back, communications), I don't see a case for why we should persist with him especially when we are paying him the salary befitting one of the best striker, creative players in the league and double that of the actual best goalkeeper in the world, Alisson.