If white wins a single game and black offers a rematch, white should accept or give a real reason why they can’t (dinner, work, etc.).
I don’t always ask for a rematch, but lately more and more players are declining a rematch after winning one game as white. It is childish and getting worse on the site.
After two games or after winning one game as black, this wouldn’t apply.
If you are part of the problem, please stop.
I'm confident that if you got your wish you'd be back complaining how often Chess players eat dinner. Your deal with your opponent is to spend time together for one match and if you both want to play again then there are options. Many players don't want to play again straight away. Analysing the previous match would be one reason. If you want to improve, you could use that time to analyse your loss. At the end of the match you could try asking politely if they'd like to play again in the future. The more demanding that you are, the less likely it is that they'd want to spend time with you in the future.
No one is obligated to beat you twice.
Best answer of the week on the same old complaint.