I'm sure if you would ask the average frum person if they fully vote for a specific party out of loyalty to the "laundry" (like a sports fan), everyone would all say that they don't, and rather, they make logical, well thought-out decisions.
However in recent years this doesn't seem to be the case anymore, and people seem to be supporting politicians out of blind loyalty. The echo chamber issue is an issue across America, not only a problem in frum communities. This is what the letter was coming to address; we should be better than this.