Currently the main force of the non-ISIS opposition to Syrian government is the Islamic Front group, a loose conglomerate of several groups, the strongest of which is the An-Nusra front, a Syrian branch of Al-Qaeda. The both An-Nusra and Al-Qaeda are designated terrorist organizations by the UN. We heared a lot about how Al-Qaeda is evil during prevuous years, so the Western support to the "rebels" seems hypocritical.
Recently seven Western countries (the USA, UK, France, Germany, Turkey, Qatar, Saudi Arabia) had made a declaration condemning Russian bombing of the non-ISIS Syrian opposition.
So what's the purpose of doing so?
Just some comparison.
(Warning: image may be shocking to some viewers)
This is Free Syrian Army. The West heavily helps them. Russians say they do not consider FSA terrorists and do not bomb them. FSA as of now a weak group, mostly integrated with the structures of Islamic Front while formally remaining independent.
This is An-Nusra (Al-Qaeda). Russians heavily bomb them, but the West condemns Russian actions.
This is ISIS, Russians bomb them but only slighly. The West wants Russia to bomb them more and bombs them themselves.