I really feel like people should say this to me more often, because I do like to explain things, and that can come across as very patronizing! The curious thing about the verb to patronize by the way, is that, like many English words, it can have more than one meaning.
There’s the negative and probably more common meaning of to act in a superior manner to someone, usually by superficially appearing helpful or kind. But if you patronize a business, it simply means to be a customer there, usually regularly. How can the same word have such different meanings? To find out we have to go back to Latin.
The word patron entered the English language in the early 14th century, and meant master or protector. By the end of the century it had also come to refer to someone who supports a cause, usually through their wealth or power, such as a patron of the arts, or of a specific artist (the online artist-support platform Patreon refers to this meaning of the word). The verb to patronize developed from this, and is used in reference to businesses because by frequenting a business, you’re supporting them, just as someone might be a patron of a cause or artist.
All of these words come from the Latin pater, meaning father, with the idea being that a patron defends and protects their cause like a father does with his children. Therefore while patron referred to a master, it was usually with a benevolent sense.
At some point in the late 18th century, patronizing meaning condescending came into use. It’s unclear why it had such a negative meaning compared to the existing similar words. Perhaps it’s simply something that happens over time when a meaning has become so established: it’s inevitably going to be subverted.
Still, it’s not like the meaning is completely unrelated: the basic idea behind both meanings of to patronize is to act as though you’re in a position of power over someone, and to support them using that power. It’s just that one is negative and one is positive.
Ah, but you’d probably figured all that out anyway and I’m just patronizing you!