I am obviously missing something.
Yeah, you're missing the manual, the section you will find the explanation in is titled "Running Windows applications from the command line".. This is the Linux manual, and it explains the command line arguments, which is expected by the Linux folks like myself. Obviously, the Mac manual is built with the idea that Mac users don't want to know about command lines. At the very least, I couldn't find that info in there... Don't complain to me, I have nothing to do with it... 😋
What you're doing wrong is that you're just pointing to the windows executable, as if it runs on its own on Mac (or Linux):
~/.cxoffice/MailWasherPro/drive_c/Program Files/FireTrust/MailWasher Pro/MailWasher.exe
The problem is that you must invoke the translation layer that allows it to run, in this case Wine/Crossover. I'm avoiding here the mention of escape characters when using paths with space in them, I'll save that for later. At the simplest, something more like the following is needed:
~/cxoffice/bin/wine --bottle MailWasherPro --cx-app MailWasher.exe
You will notice that we precisely invoke wine, tell it which bottle, and then let it search that bottle, via cx-app, for the correct executable. This is all true, provided that the script cx-app exists in the Mac version of Crossover. If the stuff I wrote above doesn't work, I think you should open a support ticket with the staff. I'm sure that if my stuff fails, they have a way to do it for Macs.