Everyone that had an animated avatar before the rule changed were allowed to keep them (for now). They won't be able to upload a new animated avatar.
OK, APNGs are now detected. Old ones are grandfathered for now, in part because people have ongoing campaigns, but in the future I might (or might not) go through and remove them.
That solves my confusion thank you.
Those animated avatars you saw has the format of .apng or animated .png and not .gif that's why it's not against the rules related to avatar.
However, saw some threads that theymos prohibited uploading those format few weeks ago, those animated avatars are uploaded before theymos performs to disallow of those, so you can't upload those format from now on.
[Edit] It's quoted above.
Thanks for the info, some might find animated images irritating so it's a good decision by theymos.
My question has been answered I will lock this thread now.