Patients in hospitals, either ill or injured, are a protected class under the Geneva Conventions.
Again, not a clear-cut issue. You cannot extrapolate a few lines from the Geneva Convention with your own definitions of what constitutes a "patient". So again, since this misinformation is being repeated, I find it only fair to quote a few passages on why that is, at least, debatable and why it is still indeed very important to add that the 3 killed were terrorists, were carrying guns and were planning a terrorist attack.
The Geneva Convention provides guidelines for the medical treatment of enemy wounded and sick, as well as prisoners of war. However, there are no comparable provisions for the treatment of terrorists, who can be termed unlawful combatants or unprivileged belligerents.
(there wouldn't be an article about it if it was an obvious question: https://pubmed.ncbi.nlm.nih.gov/19998085/ , you should contact that journal and ask them to retract that article since you seem to say that they're wrong)
Qualifying as wounded or sick in the context of international humanitarian law requires the fulfilment of two cumulative criteria: a person must require medical care and must refrain from any act of hostility. In other words the legal status of being wounded or sick is based on a person’s medical condition and conduct.
(https://ihl-databases.icrc.org/en/ihl-treaties/gci-1949/article-12/commentary/2016 )
Being an active terrorist member of Hamas and Islamic Jihad, carrying at least one gun, planning a terrorist attack, and very likely committing perfidy by hiding as civilian patients in a hospital, all of that is certainly NOT "refraining from any act of hostility". You're free to consider the more general moral debate on whether it's okay to assassinate terrorists hiding in a hospital, but it's wrong and misleading to make the Geneva Convention say what it clearly doesn't say at all.
What would have clearly defended the terrorists' right to care would have been if they surrendered and left Hamas. But in the absence of that, it's, at best, still debatable whether the First Geneva Convention defends those terrorists' right to hide as civilians in a hospital to "receive care" or not.
With all this said, yes, it is very much indeed misinformation to maliciously leave out the fact that the 3 killed were Hamas and Islamic Jihad terrorists.