Technically yes, you are breaking and entering under what I can find as the legal definition of breaking and entering in the US (IANAL and don't live in the US even):
https://www.law.cornell.edu/wex/breaking_and_entering
Breaking and entering is the entering of a building through force without authorization. The slightest force including pushing open a door is all that is necessary. Breaking also includes entering a building through fraud, threats, or collusion. To constitute entering, it is sufficient if any part of the accused’s body is introduced within a building. It is not considered breaking and entering if the premises are at the time open to the public or the person is licensed or privileged to enter.
So the fact that you wanted to do a good deed is not relevant for it being considered breaking and entering. If only the door was already open and you shoved the package inside without actually ever even having an atom of your fingertip enter the house itself, then it would not have been "breaking and entering".
I completely agree though that nobody in their right mind should want to prosecute you for this. This is the differences between the actual letter of the law as it would be applied by a computer algorithm automatically and a good judge / jury that interprets the law and the facts.