I see nothing wrong with him providing a free community version and a paid custom enterprise versions.
How? For me the interpretation is straightforward: if you create OSS in the hopes of making money from it, you might succeed but the odds are overwhelmingly against you.
Ultimately, the only success guaranteed when you open source a piece of code is the fact that you... Open sourced a piece of code. There's now a new library/tool/application out in the world for everyone to see.
That's how I interpreted the other comment, and I wasn't even too charitable.
In my sibling comments I explained more about disagreeing with the starving artist vs business enterprise false dichotomy.