@molsson - I will say privacy.. Not always web app is the best solution... ;)

I develop a similar desktop application called Text_Comparer [0], days ago I update it to v1.7.2

Includes features that cannot be found on ModernCSV or Rons CSV editor, read the included help.md

[0] https://www.pipiscrew.com/threads/text_comparer.42/

if you cannot access the page, try a proxy.