Schwarzer feels the Liverpool keeper has been unfairly portrayed by his critics.
He wrote for the Daily Mail: "I have found that if one person says something about a keeper, the others tend to agree rather than challenge. The tendency is to go with the opinion on the table rather than form their own.
"People do not recognise when he plays well because it does not fit the story. When Liverpool were very close to winning the league in 2013-14, Mignolet was a key man. Now people are jumping on the bandwagon and, instead of analysing the goals that Liverpool concede, the stock comment is that they will never win the title because he is not good enough.
"That is unfair. You expect it from people on social media, but not former players."