If the concern is the journalistic integrity of a tech news blog whose founder also funds certain startups likely to wind up in the tech news... one way would be to make those investments subject to an NDA I suppose. None of the blog writers would know which companies were or were not funded by the founder's fund.
Or a news blackout could be imposed on that blog for any companies funded by the founder's VC firm. I suppose the news blackout would be an imperfect solution, since presumably reportage on any competitors to the portfolio companies could be viewed as suspect.
Even if Mr. Siegler insists that the tech blog where he works is a cool place founded by a cool guy, that does not address the perception of the blog from the outside. If there is any perception at all of potential bias, then both the VC fund and the tech blog suffer an erosion of perceived integrity (regardless of whether or not that is actually the case).
Independence is a tricky thing. I think maybe if TechCrunch were not part of AoL, then they could potentially pull off this balancing act. They have enough momentum now that readership won't evaporate overnight, and a few blog posts critical of portfolio companies or complimentary to competitor companies would re-establish their credibility. But a big corporate parent is not going to like that kind of the seat-of-the-pants approach to managing risk. Doubtless somewhere in the bowels of AoL somebody is running the numbers of what would happen if somebody sued along the way, and not liking what they see.
As for Mr. Siegler ranting about his employer on a blog they own, that strikes me as a classic CLM. Big ol' corporations really really tend to hate it when someone down on the front lines starts to think they're irreplaceable and they can do as they please, just because they've taken a lot of bullets and led a few charges over their little piece of the battlefront. A better approach would have been to tactfully address all of the issues he addressed, in the interest of informing the readers, and with the same goal of trying to gin up reader support. But he could have mentioned that he really appreciates the resources at his disposal thanks to the AoL acquisition, and he believes that TechCrunch adds value to the parent firm primarily due to its unique editorial independence policies, etc. As it reads now, he comes off as churlish. Nobody likes to have f-bombs hurled at them, not even dull gray corporate types in upper management. It really burns when those f-bombs are lobbed by someone on the payroll.
IMHO, if Mr. Siegler truly wants to help his boss keep his job, his best move now would be to pull that little rant pronto, and edit it to be a lot more polite and respectful to AoL, throw in some mea culpas about getting wound up too soon, etc. and then re-state his case in terms that corporate can understand and appreciate. AoL might be a bunch of assholes, but they are the assholes that cut his check.