It isn't unfair. Bale plays the majority of his games on the wing and gets plenty of space created for him and gets the ball played to him in dangerous areas lots of times. The main sacrifice he has to make is not receiving the ball as much as he would like as Ronaldo is the player who receives it the most. It is not like he tracks back much like lots of the other players, including Benzema have to. Despite all that, it just hasn't happened for Bale this season after having an impressive first season. The point about Suarez was that he is not playing with the freedom he had at Liverpool and he has had to make sacrifices, yet is still thriving. Maybe Bale does not have Messi to bounce off, but Benzema is not a bad player to bounce off too. There is no reason that Bale should not be doing better also. He showed that he could do it last year.
I do not see what the other players not being attacker has to do with anything. The point is that they are not being played in their best position and have had to make sacrifices for the team. James has had to play much deeper than he does for Columbia and he has spoken about that in many interviews and about how he has had to adapt to his deeper role. Isco is an AM who has had to play deeper this season also. He couldn't quite adapt to the position last year and he lost his place but this season he has adapted to his role and has been excellent. Di Maria's main position is as a winger but he showed his versatility by playing as a CM last season. Bales poor season this year is on him, not the team. He showed he could play well last season when being used similarly so I do not see why he should not be able to do so this season.
Again, Suarez' situation is not at all similar. Playing in a fluid front three with Messi is nothing like playing in a more rigid forward line with Ronaldo. Suarez might not be the 'go to' pass like he was at Liverpool, but Neymar and Messi, in particular, are certainly team players. The 'sacrifices' for Suarez are minimal, to be honest. He's not playing with a Ronaldo-type, who'll openly scowl at him for daring to miss. It's not a million miles away from his Liverpool set up.
Well, quite clearly not being an attacker makes a difference. Isco is essentially playing an extension of his usual role. Di Maria isn't/wasn;t ever a goal-scoring match-winner. It's not a sacrifice in the same sense. Again, he was doing the support role he's always done. I didn't watch much of Rodriguez at all in France, so I have no idea how things have changed.
Bale isn't blame free, but he's extremely similar to Ronaldo in style, and Ronaldo is not only top dog, but he's not a team player whatsoever.
It's a complete miss-match of styles - much like Di Maria at United. Like I said earlier, they're better off doing themselves a favour and swapping clubs.
For me, it seems quite clear that back in this league, being more of the main man, Bale would look the player he did at Tottenham.