Glen Beck is a TBM (true believing Mormon). No, to condemn them is to get them to see what is wrong and show others what is wrong.
There is a campaign that did what you suggested, it failed miserably because it didn’t reach any Mormons or get them to leave and come to Christ, instead it reinforced the their belief that they were Christians. It was a campaign where Christians hugged Mormons and agreed with a verse in the Book of Mormon.
I don’t just do this on FR. I worked for a ministry to the LDS (volunteer). I have done this for almost 20 years now. I’ve met with them in Provo and Salt Lake. While your idea SOUNDS nice, it doesn’t reach them. You have to first get them to see the errors of Mormonsim before you can ‘love them to the Lord’. It is a 2 step process and the first step (extraction) is hard and brutal - but that is the only way to break through the brainwashing.
“Washing their feet” just reinforces their deception. Getting someone out of a cult is far different than reaching non-believers or agnostics.
It worked very well outside Utah
I will say, that one of the Mormon’s said to use that you wouldn’t even convert someone in Utah because their entire family is there and the community doesn’t look kindly on people that convert.
Outside my experience.
I wish you luck. I think you are dealing with a bulwark community that is wrapped around this religion/cult very tightly.