Go ahead - disagree!! You are perfectly entitled to do so.Since I am already being a contrarian in this post, permit me to also disagree with your assessment that a damaged Leicablad lens is the saddest sight in all of photography.
??? - WHO intended what??? I'll agree that the Optical Engineers were involved - I've known and worked with a few.To me the saddest sight in all of photography is a fantastic lens with a UV filter on it. IMHO a person who is willing to pay the bucks for fantastic lens should also be willing to take the risk of letting the lens do what it can, in all its naked splendour.... as the lens engineers (and indeed, God Himself) intended for it to be used.
Uh ... Permit me to say that it somewhat presumptuous to assume the intent of the Great Creator. Possibly, in some grotto, on some Chapel ceiling ... we might discover a painting of the GREAT ZOT ripping a filter from a lens amid flashes of lightning and thunderous peals of thunder - so far I know of none even remotely applicable. Until I do, I'll limit any discussion to the engineers.
While I'm at it - I have never encountered ANY optical engineer with such a negative evaluation of filters. Period. As long as the geometry of the filter is reasonably sound there is/ can be - VERY little effect on the ray tracing and finally, image. Way back, I was presented with the idea that the thickness of a filter had a negative effect on image quality. As an experiment, I set up a lens on the optical bench, observed its characteristics - and introduced what would be an unreasonably thick filter, in the form of a double surfaced fused quartz optical flat. Fused quartz, with a HIGH refractive index, complete with "seeds" (small), and -- ~ 40 - 50mm thick. End result? No ... NO significant degradation of image quality.
Now ... Water is not appropriate for removing oils. True.
In trying to remember, I can't think of any instance where I have encountered oil contamination, Must be that my (demon) UV filters are woring well.
But then - there are those who would advocate the use of Drano and a grinding wheel...
We did have one techni ... uh, well not quite ... who decided to clean a lot of 20 specially coated (20 layers) lenses... his choice of cleaning media was a common pencil eraser.
He never got a second chance.
BTW ... Surfactant? Wouldn't that decrease the surface tension and increase the possibilty of accidental incursion ito the innards of the lens?