It's not oracle specificaly it's that if you are say a structural ironworker during the day and make bronze sculptures as a hobby then a judge will understand they are different.
But they might not understand that being a sysadmin is as different to being a web designer in the evening.
As I understand it, Oracle's standard employment agreement includes language saying you agree that Oracle owns every idea you have while employed by them, whether on "paid hours" or not, whether related to databases or software in general or not - if you're a database engineer for Oracle and you invent a better tap washer, Oracle seem to think they'll own your plumbing related invention. There's workarounds for at least limited exceptions to that standard rule, but it's apparently unusual and required signoff at many levels above the typical workers management.
But they might not understand that being a sysadmin is as different to being a web designer in the evening.