Most of the time, your right about deserved corporate suspicion.
However, CEO of Tumblr, Matt Mullenweg is all about open-source. In his July 2022 interview with TechCrunch, long before Musk bought Twitter, Matt laid out his goal to make Tumblr open-source: https://techcrunch.com/2022/07/05/matt-mullenweg-wordpress-found/
So I join your caution with most tech CEOs but I have a lot of trust for Matt #Mullenweg: https://youtu.be/AaacWgrCX3Y