if Russia deems ISIS to be anti-American, then it will support it.
I don’t like the guy, but Putin is supposed to look out for the interest of his nation (and his crony friends) - not ours, or NATO, or the UN.
However, you are crazy if you think Russia would support ISIS. ISIS is a major threat to Russia and it’s allies in the region. ISIS is close to them geographically and Russia has a large Muslim population - especially in the areas close to the proclaimed caliphate. ISIS is also a major threat to Russia’s allies in the region and governments that are friendly to and trade with Russia (especially Putin’s friends).
On top of that, Putin has publicly stated several times that he will destroy ISIS. If he fails to keep his word that is a much bigger deal in his own culture and country than Obama’s “red line” was. Putin is also using the fight against ISIS to reassert Russian influence.
There is NOTHING to support your suggestion that Russia will ally with ISIS.
Why would you say that? Putin supports Chechens when it is “convenient” for him. Why wouldn’t he support ISIS if it is convenient? Because you believe him when he says so? LOL