If there were no signs of drunkenness, and it was only a slanderous attack, as you said, then you make Peter a fool.
Obviously, the people thought they were drunk so much so, that Peter had to address them, NOT for slandering, but for actually believing that they were drunk. This is obvious. That is why Peter said, "These men are not drunk as you suppose...".
Peter believed that the people actually supposed they were drunk.
If what you say is true, you make the Apostle Peter into a fool.