So they can't say "Sun is doing a good job at open-sourcing their own software" because then they'd be asked "so why aren't you doing the same?" - and because nobody likes to admit a competitor is doing a good job.
So we get these mealy-mouthed attacks instead.
Given that DTrace has been integrated into MacOS X into Leopard:
and that it's also being worked on for FreeBSD, isn't that proof enough?