Although I agree there is healthy Syrian opposition, in some of those areas there is indeed, Al Nusra.
The Russians have met with “legitimate” or “healthy” Syrian opposition, the opposition is meeting in Kazakhstan presently.
Adding to what I wrote above, I suspect Obama may have been weak and ineffectual on going after ISIS for the deliberate purpose of providing Russia the opportunity to move in and ultimately take over the Middle East. Meanwhile, Obama and Comrade Kerry huff and puff like they’re all upset about it.