I think there are different style guides for each. I don’t understand why you put them together. We were talking about a HTML guide style, not about having one for both of the coding languages. Though I can understand you and agree with you on the practical aspect, my observation wasn’t on what’s the best way to code, but regarding how a style guide should be. As mrf said, we should look for objective directions. You cannot be subjective with the minimum requirement. The fact that different files types (HTML and XML) have different minimum requirements is not subjective. The point wasn’t to create a universal style guide for all the coding languages but a style guide for each one of them separately. Having this in mind you cannot be subjective by following the minimum requirement for each coding language. The fact that you want to have a common coding style for both coding languages is subjective.
I understand that you want to make users happy but that’s exactly what subjectivity is. A style guide purpose is not to make users happy but to guide them. What you consider to make the users happy may be good, indeed, and I don’t disagree with what you consider to be good. My objection was on the subjective-objective matter, not regarding which is the best way to code.