Okay. What you said is fair so I agree with you.
You can refer to this documentation for these best practices for further reading.
In that documentation there are no explanation for the 'cabab-case' rule. So I am giving you one now.
URL's can contain two things
1. path (cabab-case)
Now you can't use cabab-case as params as most languages don't support this type of variable name( Maybe you can convert it but i guess you got my point)
So What remains is the path where it's recommended to use "cabab-case" to differentiate between the params and URL path.
I hope you understand my point.
But I completely agree with you on the point that consistency in design is the most important thing. If you want to go other way that's totally fine as long as you stick to it.