No, you'd have to really be stretching it to come to that conclusion. The questions were fair and reasonable given that the application does indeed appear to no longer be maintained and the maintainer(s) no longer appear to even be subscribed to or monitoring this mailing list.
Dia is quite obviously abandoned, the engineering effort required to modernize it to GTK and Python 3 being either beyond the interest or abilities of its maintainers.
In all fairness there should be a disclaimer on the website saying that it is no longer being actively developed and will probably stop working altogether in a few years. That way unsuspecting users won't invest any more of their time in learning a program that has no future.