This is completely normal. You can't just issue a chargeback because you feel like you want your money back after the fact. They want to know what went wrong. It could be fraud but it could be also misleading checkout experience and other reasons. The merchant is charged often a fee for a chargeback on the order of $15 and it might result in penalties.

So, if you feel like you've been charged unfairly (e.g. product not what was expected), in error, fraudulently etc. then chargeback is the route and you should provide a reason. It's a mechanism to protect consumers. If on the other hand you just want your money back without good reason then chargebacks are not the right tool. The consumer also has an obligation to pay if there was no fault on the merchant side.

Honestly, sounds like everything is as it should be?