No, the problem with attributes is that people consistently misuse them. So many things about XML break down when you make everything a self closing tag with 50 attributes. So many programmers just seem to say, "oh, it's shorter text so it must be inherently better" or "oh it's one-to-one so I should strictly avoid anything resembling a heirarchy."

Like I think this guy is mostly correct in identifying bad XML: https://www.devever.net/~hl/xml

Though I don't necessarily agree with the "data format" framing. This idea that markup languages are not data formats seems confused.

> They don't. You absolutely don't need a schema. If you declare a schema, it should exist. If not, no problem?

I agree that they should not.

However, I have used many tools that puke when presented with XML fragments or XML with no schema.

Sometime attribute use goes too far such as when they contain comma separated lists of items.

Sure, but that's not the fault of the format itself, is it? You can write extremely long enumerations in any natural language -- that's the author's fault.