1)
What is "ha'Am Eleh"?
1.
Radak: It is people who came to offer Korbanos, and people of the city Shilo.
2)
Did Eli believe what he heard? One who heard Leshon ha'Ra may merely be concerned lest it is true!
1.
Malbim (23,24): He said "ka'Devarim he'Eleh." Even if it is not exactly as I heard, since I hear it from all the people, you cannot say that it is all false. And even if you will say that it is all false, there is Chilul Hashem due to the reports. 1
1
I.e. you are obligated to justify yourselves to people - "vi'Hyisem Nekiyim me'Hashem umi'Yisrael" (Bamidbar 32:22). (PF)