POD to all the above. Ignoring her comments is fine.
If she comments to you specifically about sharing too many kittens, then you could, if you wished, respond with something like "friend, did you know you can 'hide' people's updates so they don't show in your timeline" but I don't think ignoring the comments completely is remotely rude and it's your facebook page, youcan post whatever you like.
I personally don't like game requests and so I have set up to ignore them. I'm not very interested in 'cute' pictures of people/animals I don't know, but the friends I have who pos those things *also* post other things,so I just scroll past the bits I'm not interested in, without commenting. It's not difficult.
Of course, if I could only convince **facebook** to display my newsfeed as 'recent items' not 'ramdon stories we have unilaterally decided are top stories' I would probaly see a lot fewer 'cute' posts, but I can't. It won't believe me when I tell it that is what I want...