Please, Erik, don't let us doubt well proven facts and design practises. If you think it's wrong what I recommend, then please contact an EMC expert.

I'm no expert, but what I do has worked extermely well for me. There is no way the capacitor will not make ESD hit signal ground with more gusto than with no connection whatsoever.

I do not think that "it's wrong what you recommend", just that my approach is better.

Finally, what I recommended with the soft grounding scheme is extremely widely used with professional devices
I, personally, believe that this is the case because those that included the capacitor just propagated the fact that "soft grounding scheme is extremely widely used with professional devices" by, for that very reason, including it in another "professional device".

Many moons ago I worked on a unit that regularily blew up, removing that very capacitor and providing a strong, separate, protection ground to the enclosure took care of the problem.

Erik