I have a hosts file too and a really big one because I have 3 hosts files in one.
I also have AVG Free and I have never seen it come up with anything to do with the hosts file.
Do know that doing scans that they can take longer to scan because of a hosts file that is big and I have HostsMan to manage my hosts file and I disable my hosts file when I do scan.
I see from your screen shot it says change on the hosts file. Hostsman is a great program to have and you can backup your hosts file, restore it and update it really easy. http://hostsman.abelhadigital.com/
What was change and by who I don't know unless it was AVG that changed the hosts file because it deleted something. But was what it found really something bad or not I do not know. Lots of programs that scan the hosts file and find things are false so you do not want to have the programs delete them.
I use WinPatrol too and anytime any changes are ever made to the hosts file it will tell me and it has only ever come up when I have made changes so I know the changes are ok and nothing bad was ever done. http://www.winpatrol.com/