The ATP and PTPA don't get along for obvious reasons and one of the founders behind the PTPA,
Vasek Pospisil has slammed the ATP for negativity towards his organization.
Novak Djokovic and Vasek Pospisil got the idea for the PTPA back in 2019 when they realized that the original organization (ATP) has deviated from its initial goal. Seeking to rectify that they announced their own association of tennis professionals which created a bit of turmoil on the Tour. The idea of a players union was not something new.
Andy Roddick called for that back in 2011 and several players gave their opinion on it. Andy Murray famously expressed for unity in the sport despite stating he is not against a union of players. Roger Federer and Rafael Nadal famously opposed the idea. There has been a war of words between the organizations since then and recently Vasek Pospisil slammed the ATP. He said:
“There are so many conflicts. The games have been very dirty at the ATP. The
things that I’ve heard them say about [the PTPA] and what we are trying
to do and what we are doing in the background, just all lies. The stuff
I’ve heard, like ‘the PTPA, are trying start their own tour’, lies."
He further said:
“They are saying that we are paying players to sign up with us. That
just shows how scared they are of players having a say, having a voice. They
have completely monopolized the sport. They have done an amazing job
maintaining control, and that has hurt the sport in a huge way.”