I agree !00% that what they did was completely wrong.
Unfortunately, there are many in the chareidi community whose distrust of the Israeli government is so ingrained that they are sure that most of what the government says is false. They refuse to test (unless forced to do so), largely because of the many VERIFIED accounts of people who received a positive test result on a sample that was never submitted to a lab. The government has been caught playing games with the numbers in order to make them say what they want - keeping everything open through July and August, as the covid cases skyrocketed, and then closing everything down just in time for the Yomim Tovim.
Many are sure that they either already had Covid, or are immune to it, so they see no reason to get an expensive test just in order to fly.
They are wrong, but the biggest problem lies in the way information and MISINFORMATION are spread in their communities.