No escalation of care (putting limits on treatment) and a chemical code (giving drugs to person who is dead) are not the same thing, though both are a sign of futility.
What is being referred to is actually a "slow code", the further additional of treatments despite the knowledge they will offer nothing in a person who near or at arrest (ie, the third or fourth vasopressor whose pulse waveform is becoming flat with bradycardia). Many people view that treatment as unethical, though like most ethics... that ends up being a matter of opinion. But it is futile and borders on dishonesty with the family.
I put them all into the "meh, whatever" category, same as "show codes", except chemical codes, those are just silly. Either you do a code according to ACLS/PALS or you don't.