Google "Media Matters" "Fast and Furious" and ATF and you'll get lots of links describing the ATF talking points against Issa which are basically:
1. The real problem here is weak gun laws, not this program.
2. Poor ATF lacks resources (while of course neglecting to mention that in 1994, 2,500 agents were responsible for 284,000 FFLs. In 2010, 2,500 agents are responsible for 60,000 FFLs
3. Darrell Issa knew about this all along and he was OK with it.
4. The idea that this was done to promote gun control as policy is ridiculous conspiracy theory on par with birtherism.
As you can see, they studiously avoid discussing whether the operation was a good idea because it is so obviouslly stupid that they don't dare have that discussion - and naturally, they don't have the least interest in discovering who was responsible for such a poorly conceived operation.
However, Fox and the NY Post have now come right out and said that this was pretty clearly not about law enforcement. Several other news organizations are starting to gently hint at it in their reporting.
And in other news, Rep. Issa's staffer has assurred the media that the investigations will continue and that Melson's resignation (if true) is the beginning of this story, not the end.
So I think the jab at Issa in the Post is mostly just a desparate attempt to try and get him to accept Melson's resignation as an appropriate sacrifice and let the whole thing slide... but I don't see that happening.