None of the people complaining are the developers (the developers like Java). They're all (enterprise) end users. The "modern" solution is something where the customers don't know it's Java, don't have to hear the words "tomcat" and don't bring to mind all the baggage associated with those names.
There's nothing wrong with Perl or PHP either, but plenty of end users have seriously negative associations with the technology and will blame every fault on the technology because it's had a rough history. All of those languages/ecosystems scream "dotcom" to enterprise users and they don't want to hear that they're paying $1.5m for a system that's built in what they consider to be legacy languages.