First of all, I'm sorry that a schedule change forced you to change plans. That really sucks. Having said that, I think it's quite unreasonable for any airline employee to explain why a schedule changed. It happens all the time. A front-line agent would have absolutely no idea why.

As for the alternatives, a quick check on Google flights shows several *A options on LH each way, but none that would've gotten you there in the morning. All of that is moot, though, since you've already rebooked.

When a schedule change happens in advance, it's good to know what your options are before you make a call. However, your options will undoubtedly be limited if you're traveling to a destination that only gets once daily service from the airline you want to fly on. Just my 2p.

As an aside, I'm not sure what the EU regulations are regarding schedule changes and/or cancellations in advance or if that would apply.