Talks over the deal, which would have brought Juventus striker Vucinic to San Siro in exchange for Colombia attacking midfielder Guarin, broke down earlier this week after Inter fans reacted angrily to news of the potential transfer.
Juve chief executive Giuseppe Marotta slammed Thohir on Wednesday, criticising the Indonesian for pulling the plug on the deal shortly after allegedly agreeing the switch via text message.
However, Thohir, who secured a majority stake in Inter back in October, has hit back at Juventus for making details of the negotiations public.
"Throughout Inter's long and storied history, the club has always stood for integrity and honesty, and we have made it our mission to uphold and continue that tradition," Thohir said in a statement on Inter's official website.
"During the January transfer window, Inter has taken part in numerous private discussions to improve our club both on and off the pitch.
"Conducted in a professional manner these discussions should remain private, making public comment before the negotiations are final only hurts the process.
"In everything I do, I believe there are core principles of success, including being hard-working, honest and reliable. I am committed to living out these principles with Inter and pushing the club to achieve at the highest level.
"As president of Inter it is my role to evaluate the performance of our personnel and challenge myself and our entire club to excel - management, players and staff.
"I cannot allow anyone outside our organisation to publicly critique our internal processes, and will defend Inter and what we stand for with everything I have.
"At Inter, we have always acted responsibly and in good faith, and will continue to make decisions that are in the best interest of the club both now and for the future."
