Seems to me that most are talking about features that are foreign to them. They assume something must be hard to read if they don't know what it means. For example, someone who just knows assembler might not understand Java (for loops? objects?), but that doesn't mean Java is generally hard to read.
The primary culprit is regular expressions and the related ops. They don't realise that the full page of code it would take for them to do the same without that regular expression would be just as unreadable as the regular expression.
One place where I would agree with them is the overuse of global variables.