Personally I think you are more right with the limited sample size than no DBs in the first. Maybe they won't, but I wouldn't be comfortable making sweeping generalizations based on two drafts (I'm breaking from the Fisher doesn't take OL in the first round maxim, and that is an 18 year old pattern!

).
I think they were targeting Blackmon in 2012 but got sniped. Plan B, they liked Brockers more than Claiborne. In retrospect, that was a great call, Brockers looks like he could be a future Pro Bowler, and Claiborne could be a bust. Certainly some teams like to build from the inside out, and we already had Long and Quinn, so perhaps he envisioned a dominant DL as a strength of the defense and team as a whole (he also added Langford in free agency). This would also answer Gilmore (and don't forget, in bypassing Claiborne and Gilmore, they got not only Brockers, but the DAL second, which alas they wasted on Pead, but intended to use on Kendrick's or Wagner) and Kirkpatrick (who also hasn't set the league on fire - at some point, if a pattern emerges and there is a recurring theme, maybe we should just credit the front office, coaches and scouts with doing a good job in passing over Claiborne and Kirkpatrick for Brockers?).
He turned down Jenkins at #33, but we did have a screaming need at WR, so that could have been a case of one bigger need trumping another. They did take Jenkins a few picks later, so that could have been a case of them being confident he would drop with his off field problems (again, we should credit them for being right in this case), and/or putting a price on how much he was worth given his well documented risk, and not wanting to exceed it. We don't know how they graded Vaccaro or Reid, though they look like outstanding players, but I can see how they might have coveted Austin more, and felt like it would be easier to get a safety like them the following year easier (perhaps in free agency or the draft) than a WR like Austin. I am going under the assumption Fisher and Snead realized that they wouldn't be able to fill all holes in the 2013 draft, and it would be a multi-year process.
I didn't read into passing on Trufant (ups and downs but great NFL bloodlines and looks good) as an indictment of all possible future first round DBs (they did take them in the first round in TEN, for instance Pacman and Michael Griffin, among others) when they parlayed that trade into Ogletree, a third used on Bailey and a sixth packaged with their own for the fifth used on Stacy... this has to be the single best trade they have engineered so far? As to passing on Elam (I like him but he is undersized), Cyprien and Slay (underwhelming rookie season), Snead and Fisher talked about how they viewed Ogletree as a top 10-15 overall talent (which those DBs weren't), if not for the off field question marks. Once again, we should credit the team for excellent scouting. They may have been right that he was a better straight up BPA, as well as filling an equally pressing and critically important need. IMO, not only is he already our most athletic, talented and playmaking LB, but has a chance to be one of the best in franchise history. That takes precedence and primacy over the likes of Slay.
Maybe they won't take a DB in the first, but if one is clearly the BPA, I don't see why they would hesitate?