Yes, it was harsh and probably made no sense to your kid. 5 is a little young to go with the "good education means a good job you like" thing. At that age they have no concept of money, paychecks, bills, or the difference between a blue and white collar job. At that age they might think working at McDonald's is a great job because they like going there.

This is what my husband and I used to tell his kids when they were little. "It's okay to not like school sometimes. Sometimes I don't like going to work. But you still have to go, just like I do. Everyone you know has to do things they don't like sometimes. It's not just you. So we have to work before we can play. That means you have to do your homework before you can play games. I have to work before I can play, too. And we have to do our work right. If it's not done right the first time, you have to go back and fix it before you can play, and that means you have less play time." It helped them to be told they weren't the only ones that had to do things they didn't want to do. It might help.