Kinda has to be, 99% of the TV audience couldn't guess that Theon being flayed on a giant X meant he was being held by the guy who's banner is a flayed man on a giant X.
Little hints here and there don't exactly work on the show.
The problem is that these hints have answers. You could observe the flayed man sigil and infer what happened at Winterfell or equally you could have read the books or the wiki and know the answer. If you guess correctly people will think you know spoilers, if you are incorrect you invite discussion which in many places causes unwanted spoilers.
That is why mystery doesn't really work on GoT, you can't theorize about something when the answer is known.
They're obsessive to the point of ridiculousness - well, Linda is. Elio tends to enjoy the show to a degree. Linda is still mad about eye colors, names, etc.
Personally I'm not a big fan of the show, but I tend to view it as separate from the book. As long as it has the general spirit of the adaption I'm fine - and it usually does. I get upset when changes produce bad television - Dany in Qarth, Jon and Halfhand, everything about Stannis, Theon etc - but good changes are fine with me. For instance I've watched about 17 minutes of the review and they barely talk about the show - acting, writing, etc. Everything is about "x was changed."
One thing I agree about: the lack of any subtlety on the show is annoying. More than a year ago I predicted Oberyn would have a bisexual sex scene in S4, and lo and behold he does. It's just so obvious.
I listened to their season 2 and 3 recaps and I thought they were entertaining. Listening to them nitpick about the book differences can be annoying but Elio does have some good thoughts on the show and how arcs have progressed. Linda, as you say, is a bookthumper.
They defend "George" to the hilt even excusing scenes from the episodes he has written. And when responding to the allegation they don't like any deviation from the books they pick something that was added (Theon in the Iron Islands) instead of something that was changed.
Some of the changes are interesting to look at season to season, in between each show seems small minded. I was particularly stupefied about their anger with the change from Jane to Talisa and how it would have been better if they were informed about the change. They were upset that they were dis-empowered by not knowing a character that was influencing the story.
They talk about Arya's arc and how Harrenhall wasn't the making of her but that would have seemed really unnatural if we had to witness the full cruelty of the books, akin to the extended Theon torture. Instead they pushed her development down the road and the key to her character changing is witnessing her family be ambushed and unable to do anything.
It is hard to develop characters like a book on TV without it either stalling the show or come off as forced. You can't get into a characters mind in the same way.
There was also a lot of talk about whitewashing Tyrion but really we needed a hero in King's Landing as the story is really being told through our heroes. Sansa is in KL but she doesn't give us a glimpse into the real power. We don't spend much time solely with the villains. As Tyrion falls outside of power in KL I expect Jaime to be our focal point, he is already being shown in a much more favorable light.