Rav Yohanan got mad at someone, and then asked why they had not told the people in the city to do 2 days of yom-tov.
(a) Who did Rabbi Yohanan Get mad at? And who was he talking to? Is it possible to explain that eventhough he was angry with his talmidim (ikpid) he was talking to the people of the city and asked them why they didn't know, because his talmidim should have told them.
(b) And secondly, is it possible to explain that he was angry with the people in the city because he assumed that his talmidim told them to have 2 days of yom-tov, even if they really didn't tell them?
(a) Rebbi Yochanan was angry with his Talmidim, and it was his Talmidim to whom he spoke.
It is unlikely that he was speaking to the people of the town, because the implication of the Gemara is that he was not in that town (but rather his Talmidim traveled there, and either they or someone else returned to him and told him what transpired). The Gemara clearly says that his Talmidim did not intervene in the practice of the townspeople, and it was that lack of intervention for which Rebbi Yochanan rebuked his Talmidim.
(b) It is possible to explain that way, but that does not seem to be the P'shat of the Gemara. Rashi says that these Talmidim "heard from his mouth [this ruling] and therefore he was angry with them," clearly implying the Talmidim and not the townspeople. Moreover, the Gemara says that Rebbi Yochanan "heard" what happened, and not that he "assumed" what happened,
and there is no reason for us to assume that he heard an inaccurate report.
The question which we are left with, though, is why the Talmidim of Rebbi Yochanan actually acted in this manner, if they knew their teacher's ruling on the matter.
All the best,