I'm Still Confused, Folks

It looks like I'm full of questions with no answers today. Can someone help me with these?

Why is it that any talk about Senator Kerry's public record on:

• His tour(s) in VietNam.
• His VVAW activities.
• His time as a criminal defense lawyer.
• His time as Assistant Governor under Dukakis.
• His years as a United States Senator.

are off-limits and consist of mean, nasty, dirty politics. BUT:

• Personal attacks against President Bush and Vice President Cheney about possible drinking problems.

are just fine and dandy?