Swimming has been engulfed in a doping row following revelations in April that 23 Chinese swimmers failed drugs tests ahead of the Tokyo Games in 2021 but were not sanctioned.
The World Anti-Doping Agency (WADA) accepted the conclusion of Chinese officials that the case was caused by food contamination at a hotel, triggering strong criticism from the US anti-doping body USADA and several top swimmers.
Asked whether he had confidence that governing bodies had created "a level-playing field", the American Dressel was succinct.
"No, not really. I don't think they have given us enough evidence to support them with how this case was handled. To answer your question -- no," he said.
Dressel will be aiming to defend his 50m freestyle and 100m butterfly individual titles in Paris.
Brent Nowicki, executive director of World Aquatics, said he was saddened to hear Dressel's views.
"This entire team, entire organisation works tirelessly. Every day they go to work and pour their heart into what we do. So when you hear someone like Caeleb say that, obviously it is not what you want any athlete to say," he said.
Nowicki said that swimming's governing body needed to work to regain the confidence of its athletes.
"We have to look forward, we have to regain his trust and those athletes' trust who share that same opinion, that's why we go to work every day and pour our heart into this," he said.
"I would invite you to ask the same question in LA (2028 Olympics).
"My goal, my hope is that his mind changes and that's why I have to work harder so that in four years' time, he says, 'They did what they said they were going to do'."
