Pogba was sent a series of racist messages on Twitter after his penalty was saved by Rui Patricio to deny United victory at Molineux.
"It's not something we should be speaking about, because it should have been eradicated a long time ago," Mata said in an exclusive interview with ESPN FC.
"That's one of the things about social media. It's fantastic to connect people if you use it for the right things.
"But it also gives a chance for so many people to let go of their frustrations towards other people and with no problems because there are so many fake accounts. There's no identity. Then you can say whatever you want and you are not punished.
"It's a problem. Unfortunately some people do that and it needs to stop. It's cowardly to do it that way because no one can see you. It's not nice."
The incident marred a mostly positive night for Ole Gunnar Solskjaer's side, who have four points from two games after being handed a difficult start to the campaign with games against Chelsea and Wolves.
The atmosphere is more buoyant than a year ago when United -- then managed by Jose Mourinho -- started with two defeats from their opening three games, including a miserable 3-0 home defeat to Tottenham.
It is the start of Mata's sixth full season at Old Trafford after he agreed to a new contract in the summer.
"I'm very happy to be here and very happy we have started the season," said Mata.
"The [summer preseason] tour [to Australia, China, Singapore and Wales] was a nice few weeks for all of us to be together. We are only starting, but we're happy.
"I would be happier if we had six points. That's what we felt after the Wolves game but the first game was very good against a good side [Chelsea].
"We've got four points, but we're looking forward to getting three more on Saturday [against Crystal Palace].
"Every time that you start a new season there is excitement. We have a manager that everyone knows, he's been around the club for many years and has done great things here.
"We are all very excited about what we can do. Hopefully we can have a great season and keep our fans happy and excited until the end of the season."