Human beings are driven by emotion. They may praise someone today and condemn them tomorrow. Just look at how Araghchi was celebrated at the beginning of the war compared to the criticism he faces now.
Iran has a population of nearly 93 million people. What concrete evidence do you have that a majority of them support the IRGC? I'm specifically referring to the IRGC, not the elected government or the Iranian state as a whole. Those are not the same thing.
Unless you have credible, representative polling or other verifiable evidence, claiming that the majority of Iranians support the IRGC is simply an assumption, not a fact. In reality, public opinion in Iran is complex, diverse, and difficult to measure with certainty.