That doesn't mean it isn't sloppy though, and while I can sympathize with scientists' decisions not to release their data or their methodologies -- they aren't well-enough funded to spend their time answering the various challenges of laypeople that aren't educated enough to understand the field -- it's still a really poor choice in the longer term that's going to result in a lot of suspicion regarding their work.
Or, alternatively: we're seeing some confirmation bias at work.
This is a really, really basic part of scientific research. Failing to do it should raise huge red flags.
"Climate change denial" has become secret code for, "I'm a neo-conservative and I really want it stick it to Those Damn Liberals(tm) because not only do they want to take away my Hummer and my hamburgers, they want to take away my guns too!"
There are plenty of journalists and talk-show pundits on the conservative side of the spectrum that see this as some sort of vindication that they were, "right all along," or just as a chance to get all sorts of coverage/attention/viewership/advertising money.
However, there are some differences. For example, the skeptics haven't been suggesting that their opponents be thrown into jail for their beliefs. And, they aren't proposing restrictions or taxes.
Comparing crazies doesn't make for great discourse.
[Edit] I should have also mentioned that it's also important to be open about how the data is adjusted. Explaining your reason for adjusting the data is not enough.
Which reminds me. Someone commented that scientists don't share code. That's not quite true. In many areas, it suffices to share data because the analysis routines are already shared.