Jay, I highly respect your position and were I in your same position, I would take the same stance.
Like I said, though, I want to primarily cut frames and as such my target for advertising is general contractors. So in that case when things go wrong with the enclosure, it's not my neck on the chopping block. I don't want to say 'I don't care' because I do, but I'm not in the same position as you.

I'll gladly steer contractors away from anything using foam if I think they'll listen, but I don't want to ruin a good professional relationship with a potential customer or sour possible repeat work by telling a GC how to do his own job.
Having been on the other side of the fence, on the end of things that was decided by someone not doing the actual work, I respect the GC's freedom.