If you are concerned about a league player talking down union when they leave, then the problem isn't the recruiting the league player the problem is either
1 - the right league player and
2 - the reasons they are talking down the code.
I think both codes should be trying to be as strong as possible by buying up the best talent wherever possible and to be honest should have a fair structure so if there is any criticism it looks bad on the player not the organisation.
Don't know if you were responding to me, but "the right league player" seems to be what I was saying when I mentioned other league players who didn't talk down whatever code they just left when they switch. As for your second point, the reasons are largely dependent on what media source they're talking to.
From a marketing position, I see why some code-hoppers who are back in the NRL would want to talk down rugby -- that's their immediate competition, and they're in the business of the NRL business, not the footballer business. But for one, that doesn't seem to work too well; the NRL lost three of its marquee players to union this year, one to the NFL, they failed to get a few signature players to return, and they're not getting a hell of a lot of flow back from union. (And isn't there talk of Gloucester going after another Burgess brother now?)
Two, what does that say about the players who leave? If a top-flight NRL player goes off to union, returns to the NRL and talks shit about union, that doesn't do a lot for his credentials. It suggests that he couldn't hack it in the oh-so-hard NRL and needed something cushy for a while -- which is bullshit on its face, considering one of the last big NRL switcher, Lote Tuqiri, couldn't get through more than a handful of PRO12 games before getting injured, twice. Or take Joel Tomkins, who worked to crack the Saracens line-up for a couple years and made three stuttering appearances in the England 1st XV, but had a pretty poor showing and went back to Wigan -- where he started and ended up in the grand final. So from Tuqiri's perspective, what the NRL media has said is that rugby was too soft and made Tuqiri soft -- which, again, is bullshit because Tuqiri has been around long enough in both codes to know what he needed to do to be in shape, and banging reality show hosts instead of training isn't on that agenda. (To be clear, Tuqiri didn't talk down rugby, but the league press did when they talked about Tuqiri's time at Leinster.) But from Tomkins' perspective, he couldn't cut it in rugby but returned to league and thrived. So which is "easier" or "harder?" Neither -- they're different sports, and different athletes with different attributes will succeed or fail at different rates and in different ways. (For what it's worth, I haven't heard one thing from Tomkins about the relative ease, value or difficulty of one code over the other.)
It also suggests that the players who do switch codes and aren't above pissing on another sport they've played aren't really to be trusted. Who's to say they wouldn't do that to another team, or other teammates? What's that say about their integrity? If they decided to switch codes again, how ready would the other code be to take a guy who's on record saying their code is too easy to play?
It's probably in the interests of both codes keep the intercode shit-talking rivalry to a minimum. It's not going to stop code-hopping, and when it happens, both sides can use the code-hopper's experience in some other code -- especially when they return -- as a boon to those athletes' abilities and what they can accomplish.
In a way, it reminds me of the early days of MMA -- is wrestling better than jujitsu, is karate better than boxing, etc. Eventually it reached a point where they all had to be versed in different styles, but each individual fighter put an emphasis on particular attributes. Wrestlers jujitsu guys still need to box and kick; muy thai fighters still need to stuff takedowns, and boxers still need to defend against submissions. Someone like Nick Diaz may not like it, but that doesn't mean his style is "harder" than what the other guy is doing, jut that if he doesn't adapt he'll lose again.