Can I ask this short question ? is it necessary to provide details or is it enough?:
Why Russia 90% of its attacks are on Syria opposition? And not on ISIS especially both of them cause threat to Syria.
Before you ask this particular question, you should reflect and think "Do I think I know the answer to this question?" If you do, then you should probably refrain from asking the question. Stack Exchange is for answering questions. It is not a place for creating a dialog, and it is not your personal blog.
That being said, if you asked that question as-is, I would expect our members to answer it as though it were asked in good faith.
A couple of notes:
Why are 90% of the attacks Russia makes in Syria not target toward ISIS.
Is it strictly necessary to provide details? Not according to official rules.
Is it a good idea to provide details? Absolutely.
Personally, I would:
Downvote the question as stated
Upvote the exact same question if you add reasonably solid evidence for the fact you are asserting (90% figure). It doesn't have to be ironclad proof, but something that would lead me to believe that it's not just a made-up figure or a guess.
Ironically, if you don't have good evidence for your claim, you can avoid needing to justify your assertion, merely by not making the assertion in the first place and asking others to provide evidence for you, which would also be a good question:
What is the fraction of attacks that Russia makes in Syria which targets ISIS vs. non-ISIS opposition?