He's probably upset that the online editor is closed source. Personally I think that's a reasonable monetization strategy long term.
In Latex, the online editor i know (Overleaf) is also closed source.
The fast pdf generation is great but I lament on their choice of markup language, why create yet another? I'm a fan of writing content in markdown and there is at least on markdown flavour (MyST markdown) that gives the essential writing features needed for papers. (citations, cross references, figures, tables)
I can see why! Many thanks fren, this will likely make my life easier. Much appreciated!