claiming spouse's exemption

I am wondering if I am able to claim my spouse's personal exemption. We are married filing separately. She has no gross income and cannot be claimed as a dependent by anyone else. She did file a return (reporting no income.) The IRS seems to say this disqualifies me from taking her exemption, since the instructions state "if your spouse had no gross income, is not filing a tax return and cannot be considered the dependent of another taxpayer." 

 

But there are past bulletins that say only that the spouse cannot file a joint return. "If you and your spouse file separate returns, you may claim the exemption for your spouse only if he or she had no gross income, is not filing a joint return and was not the dependent of another taxpayer." https://www.irs.gov/newsroom/important-facts-about-dependents-and-exemptions. 

 

So if my spouse filed as MFS, but had no gross income and does not qualify as anyone's dependent, does this preclude me from claiming her personal exemption? (Secondarily, if it does, why? Why does a spouse filing make a difference if the other two conditions are met?)