It's legal to sell on tickets over there which it isn't here. There are legitimate ways to sell on unwanted tickets without them being highly inflated prices, i.e. by fans for fans. Paid $100 for a $70 NFL ticket last year.
So the vendor made $30 on you. To be fair if i had a ticket to sell and I knew the person they would get it a cost (included folks i dont know off here for that matter). If it was a complete stranger I would get the best possible price that I could.
Not really as the club get a percentage as well -link to the site is on the official club website. When you consider that virtually all NFL games are sell outs it's not bad for a one off on holiday. Most of the tickets are from season ticket holders (theres a waiting list for season tickets) who won't be able to attend every game....some actually only go to 1 or 2 games and any playoff games. As you say though - I won't sell on for profit.....in fact if I can't get to a home game I give my season ticket to a mate for free