It depends on what your metrics are for energy and resources. Are you talking about the end user hardware, or are you talking about developer time and effort. If it’s the former, you’re right, if it’s the latter you’re completely wrong. And while there’s merit to your point (if it is about end user storage, energy consumption, etc), that’s not really in short supply while open source developers free time is.
Where I live, most electricity is hydroelectric, nuclear, or wind. So it's really NBD to download a few extra MBs of data, especially since flatpaks aren't something you need to download over and over again.
