TBH, the point isn't necessarily whether it was forwards or backwards (same with Kolbe - was he moving on a head nod vs a foot lift. IMO the knock on was a deliberate knock on that almost certainly prevented a try, so it's penalty => penalty try => yellow card. However, we've only been shown the live angles, which are from a poor camera angle to judge by; and Kolbe knowing Ramos' routine intimately well, and going on the first first muscle twitch) - it's that it was such an important intervention, and with enough doubt, that they should have been checked.
Ultimately, it wasn't those 2 events that cost France the match - the first was too early, with too many butterfly effects, and the second was a 2-point swing. Where it was lost on the reffing was the breakdown. France kept on breaking the line, and making metres, with support there immediately, but having to fight to get illegal hands and bodies out of the way.
Which, apparently, is how O'Keefe likes to ref the matches - so it wasn't bias, it was 1 team having done their homework on the ref better.
As with the "biased against tier 2" narratives, I think the closest you can get to bias from ref.s is teams being better at adapting their play to the ref - which is a skill, and one I'm happy to accept that some teams are better than others at. England, for example, are historically terrible at it; but probably better than just about any tier 2 country, purely through having greater access to the world class referees - both for club and country.
Cheating is the longest, and proudest tradition in rugby - hell the game was invented by someone cheating at football!
"It's only illegal if the ref notices" has been a cry in rugby for longer than I've been watching the game (40-odd years).
Tonnes is missed by ref.s, because every player is cheating just as much as they think they can get away with. Generally, these things even out - it's the clear and obvious mistakes (and warnings given, but ignored) that grate on the nerves, but even then, if the ref is consistently making that same mistake, then it's your job as a player to exploit that.
And it always feels unfair to the team who fails to adapt.
ETA: I should also add the language barrier - with more matey ref.s who are warning and coaching players, rather than blowing the whistle and then explaining - if there's a language barrier between the ref and the player, then there's a delay in the instruction being registered, and a slower-to-respond player is more likely to get the whistle blown against them. That goes for not understanding the instruction and for not understanding who the ref is speaking to. I'd say this is also a problem increased when the player feels they're in the right - you still have to obey the ref, but you also have to know that the ref disagrees with you.