But the start-up in a garage example was - at least, that's the way I read it - meant as there currently not being a level playing field with respect to end users, not necessarily employees. And let's be perfectly clear here: employers that are callous with their employees data are to be avoided like the plague, no matter where they are located.

As for your customers: yes, you should be careful with that data, and no, their feedback does not necessarily fall under the GDPR, only when it concerns the privacy of the individuals mentioned therein. But normally speaking such feedback would not be about such specifics but about the product itself.

Not tracking your users has a big impact on how a company is set up, what data marketing has access to, what data system administrators and sometimes even programmers have access to. Storing your data in an anonymized way can make good sense. It likely will impact your business, but leaking of that data will impact the lives of your customers more, so that's why the GDPR is written the way it is: you minimize your footprint to that which you need and you will be doing just fine.