G'day Mercyu,
Do the aforementioned comments constitute a personal attack? As noted, I am merely stating my opinion.
Yes, "so-and-so is extremely biased, immature, and unprofessional" does indeed constitute a personal attack. *Any* statement, however incivil, however personal, could be described as "merely stating [one's] opinion", so that won't get you anywhere.
-- Mark Gallagher "What? I can't hear you, I've got a banana on my head!" - Danger Mouse