Messi also backed English football for their four-day boycott of social media in response to the ongoing discriminatory abuse received online by players.
The boycott began at 3 p.m. BST on Friday, April 30 and will end at 11.59 p.m. BST on Monday, May 3.
"I've just reached 200 million followers on this platform but given what is happening today, I'm not taking it as a moment to celebrate," he posted on Instagram.
"Of course, I appreciate all the love and support that I always receive from you but I believe that the time has come to give importance to the people behind each profile, to realise that behind each account there is a person of flesh and blood, who laughs, cries, enjoys and suffers, human beings with feelings.
"Let's raise our voice to stop social media abuse. It doesn't matter if we are anonymous, celebrities, sportspeople, referees or supporters of a game, even something who is unaffiliated with all of these things, race, religion, ideology or gender doesn't matter. Nobody deserves to be abused or insulted."
Clubs from the Premier League and Women's Super League agreed to the boycott after players such as Manchester United's Marcus Rashford and Lauren James, Manchester City forward Raheem Sterling and Liverpool defender Trent Alexander-Arnold have reported that they have received racist abuse on social media platforms.
Messi's former Barca teammate Thierry Henry announced in March that he would boycott social media until they do more to tackle racism and bullying.
The boycott is being supported by the English Football Association, Premier League, WSL, English Football League, Women's Championship, Professional Footballers Association, League Managers Association, Professional Game Match Officials Limited, Kick It Out and Football Supporters Association as well as a number of other groups and individuals in football.
Messi added: "We live together seeing and experiencing abuse, more of it and each time getting worse on each platform, without anyone doing anything to stop it. We must strongly condemn these hostile attitudes and demand the companies to manage the platforms and take urgent measures against these behaviours.
"I would like you, all of my 200 million followers, to become the 200 million reasons that exist to make social media a place of safety and respect where we can share what we want without fear of being insulted.. and stay forever without insults, racism, abuse and discrimination.
"For those of you who form part of social media and are always with me, I hope you will join me and support me in this crusade. A massive hug to you all and congratulations to all the football people in the United Kingdom for their idea of putting together against abuse and discrimination on social media."