Morality is difficulty especially in a case like this as you decide life and death. I think there could be arguments for both. By acting you kill someone and kind of save 5. Through inaction you hold some responsibility for the death of 5. I think what would be most relevant in the decision making process is what if any knowledge of the 6 people you have.

Do you know any of them? Do any of them have a visual appearance that you can relate to from your own life experiences. Theses could impact the decision making process. Excluding knowing the 1 man I think you probably just switch the the tracks. My reasoning for thinking this is simple greater good.

If 1 man dies one family and one set of relationships suffer. Where as if 5 die 5 families and relationships are hurt. I do not say this is the morally correct decision and would have to accept that I had killed a person by my actions. If I had to make a choice between letting 5 die or killing a different one by pushing a button. I would push the button. Though again this excludes all other possible relevant factors. (Though if someone did not make a choice but froze in indecision I would not call that immoral.)

The only arguments I could see for not pushing the button would require more information than provided. Excluding if you believe population reduction is actually in the greater good. Which one could make for an argument for that though its kind of a dark one.