When Barry went to the future and came back, Jay Garrick quickly warned him not to obsess over the future which is exactly what he's been doing. Not only that, but he's brought all of his friends to join in the obsession. They're clinging to the only piece of the future's knowledge they have, the headlines in that news broadcast. They believe changing the headlines will change Savitar killing Iris. H.R. showed them the future as a roll of dominoes, change one and you change the outcome. An actual good thesis on the subject. However, to me, all they're doing is changing what the headlines will read. The dominoes they're focusing on is what leads to being shown when that news broadcast gets shown. Unless one of those events directly involves Savitar and his return, their efforts are in vain, which was evidenced by Wally's vision of Savitar. That vision coming to him had nothing to do with any of the things they've done to try and change the future. Maybe Barry should've listened to Jay after all. All of this will only make them feel powerless in the end.