Regarding the people on the Kibbutz who were wearing a white shirt and Chino pants. Please note that these people were in many cases, families who got off the boat after WW2 and had nothing but the shirt on their back. They worked like slaves doing hard physical labor all week to build up the desert which was EY into the beautiful place it is today. They had no money for fancy suits. This may have been all they could afford. In addition, it was very hot, and they often had no money for air conditioning, so they lived without it. This was the only way they could be comfortable and have some Oneg Shabbos. They gave long years of their lives in addition, to serve in the army and protect their brethren. They did not have the benefit of going to college after HS and starting a rich career. They were mosrei nefesh on all fronts, and this is how they could be comfortable on Shabbos.
Let us give them a little bit of hakaras hatov.