I think there is a grey/gray area between drugs being <govt agency> approved, and being actually _illegal_ to take/administer. This no doubt varies between country.
It sounds like athletes have been using this stuff for 10 years, without anyone worrying, so IMHO it's unlikely they've been breaking laws. If it's been on WADA's "watch list" (not the banned list), that suggest that THEY don't think it's widely illegal.
(although it still might be in certain countries!)
Worryingly the head of the Russian Tennis Federation says that she will be at the Rio Olympiad.
Like to bet on that ?
From the BBC news link, its clear that several athletes have had bans of just a few months - plenty of time for Rio!
No doubt she is crossing her fingers, buying heather, etc etc ...