Fellow top-ranked player Aryna Sabalenka and defending Roland Garros champion Coco Gauff had supported the drastic step, saying earlier in the week at the Italian Open that players will likely receive less than 15 per cent of tournament revenue, well short of the 22 per cent they demanded.
The dispute between the French Open organisers and players deepened after the tournament announced a 9.5 per cent increase in prizemoney to 61.7 million euros ($A100.3 million).
Players said in a statement that their share in the tournament revenue had decreased from 15.5 per cent in 2024 to 14.9 per cent projected in 2026.
"It's more about respect, you know? Because I think we give much more than what we are getting back. It's not only for the top players, it's for all of us players," Sinner told reporters on Thursday.
"Of course, we talk about money. The most important is respect, and we just don't feel it."
Sinner said the issue had not been resolved despite the top-10 ranked men and women writing a letter to the grand slam organisers last year, asking for a bigger share of the revenue.
"It's not nice that after one year we are not even close to conclusion of what we would like to have," he said.
"So I do understand players talking about boycott because it's somewhere we also need to start. Now it's been a very long time with this. Then we see in the future."
Novak Djokovic also backed Sabalenka's comments, praising her for stepping up as a leader.
"I'm glad that there is willingness from the leaders of our sport, like Sabalenka, to really step up and really understand the dynamics of how the tennis politics works and understand the nuances and really what needs to be done not only for her benefit and well-being, but for everyone," he said.
"That's a true leadership for me and I think she needs to maintain that. I salute that. That's all I have to say about that."
Djokovic, who has been vocal about players' issues throughout his career, was one of the founders of the Professional Tennis Players Association (PTPA), which said the row over French Open prize money shows the sport needs reform.