The points raised by the reviewers are valid, you can't just optimize one variable and leave the rest as it is. even if you are intent to optimize some of the variable, you must explain why it is done and must provide the values used for rest of the parameters. All the hyper parameters used in ML model have some significance and not conveying why it is not being optimized or even not been give the value is certainly no one will accept. My suggestion would be, if you not intent to optimize all parameter then you must convey the reason and give them the default set of values used for those parameters. You need to show clearity on the purpose.
I hope this helps.