Lewandowski, who scored 344 goals for Bayern in 375 appearances, joined Barcelona in a deal worth 45 million euros ($45.98 million) earlier this month, after forcing a move from the German club.
The 33-year-old had said in May that his story with Bayern was over and he could not imagine staying on with the German champions, who were not eager to let the Bundesliga's second-highest all-time scorer go.
"I had a very good relationship with my Bayern team mates, with the staff, with the coach, and these are all things I'm going to miss because I spent a beautiful time there," Lewandowski told ESPN on Friday.
"Everything that's happened in the last maybe few weeks before I left Bayern, that was also of course a lot of politics.
"The club tried to find an argument why they can sell me to another club because before it was difficult to explain maybe to the fans. And I had to accept that even though it was a lot of bullshit ... said about me."
Lewandowski added that his decision to leave Bayern had nothing to do with the club's pursuit of Norwegian striker Erling Haaland (22), who joined Premier League club Manchester City.
Bayern sports director Hasan Salihamidzic said he was surprised by Lewandowski's comments.
"I cannot understand it at all," he told Bild newspaper. "My father taught me that when you leave you don't close the door with your behind. He's on the best way of doing just that."
