Putting it back on a shop shelf is worse in my opinion. If someone buys it then it's just sending the shop the message that meat is selling well best order some more, they won't buy less cans of meat because you put it there, they'll just think they're running low on stock and buy more. Plus any shop that sells it is supporting the meat industry too, so you'd just be giving them money by letting them profit.
Just donate it to a food bank and let some hungry people get a meal, the damage has already been done by buying it you can just prevent someone else from needing to buy more. If someone is needing food banks they likely won't switch to being vegan anyway, they've got other problems that demand more immediate attention / use of their money. You could buy a few vegan options to donate along with it if you really want.