Nah, getting a dopamine hit is the standard human reaction to getting approval, and upvotes are basically distilled approval. You can pretend you are “tough” and don’t care about “validation from strangers” but normal people get a sense of satisfaction and a desire to repeat it when they post something online that is well received.
Hell, that emotional reaction is the entire motivating factor that keeps every social media site full of fresh content. People want to be liked.