Plus Reid is pro-life and anti-gay marriage. So there's no functional difference. No "federal marriage amendment" has a snowball's chance in hell of passing. At least she acknowledges that making gay marriage illegal requires amending the constitution.
A majority of Democrats are anti-gay marriage, but they know which way policy is headed in the long run and aren't fervent about it the way Angle is. Obama is nominally anti-gay marriage too, but his behavior shows nuances and compromises along the margin that make him different from, say, Gary Bauer.