Thank you for clarifying this.
In order to increase user-friendliness of STACK, I'd propose to either suppress this issue by internal checking for conflicts in identifiers for input and feedback. It is a trade between freedom for those with a postgres database and safety for those with a mysql database. Once this seems to be a known issue, I'd appreciate being warned in the help texts about not to rely on case sensitivity in identifiers.
I just cross checked the help texts for the question text entry and the help page referenced therein. They both don't contain any hint on case sensitivity issues. Yet why should they, if the issue could be avoided at question level.
I had no idea about databases and their case sensitivity. That's why the issue took me the time worth the authoring of a whole multipart question (which due to inefficient personal workflow is several hours).
Please, dear developers, don't forget how stupid users can be!