"I like parties."
「私は党が好きです。」なぜ私はこれを書くことができない？ Why can't I write this? Sorry if my Japanese is bad, I'm a native English speaker.
I'm not sure in what context one would say "I like political parties", but you're right, it should be accepted. We'll fix it later; we would appreciate it very much if you could report it from the form instead of using the discussion board on your next occasion, for it would infinitely save time for both of us.