I'm told Art.7 requires that the EU suspend any member state using military force against its own citizens
It does not require any such thing. Not even close.
Article 7 sets out a process whereby the EU may suspend certain rights of a member state, including its right to vote in the European Council, if the state seriously and persistently breaches the values in article 2. Article 2 says, "The Union is founded on the values of respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights, including the rights of persons belonging to minorities. These values are common to the Member States in a society in which pluralism, non-discrimination, tolerance, justice, solidarity and equality between women and men prevail."
Using military force against your own citizens is not necessarily a breach of these values. It may be, for example, that a government is using force to re-establish the rule of law (not saying that is what is happening in Spain). And even if a state does breach those values seriously and persistently, suspension is the state's rights is not automatic.