Thats ghetto. If android devices, like the N7, cant connect to an ad hoc network, why do other android devices such as my one v use an ad hoc network for their Wi-Fi tethering? Its like they assume you're going to be tethering a non-android laptop instead of any number of android tablets? Not fun.
Ad hoc is sort of an obscure way of setting up wifi, and isn't really used unless you don't have an access point and need two computers to communicate with each other over wireless. Although I can't really think any reason good why Android can't use them, if iOS and even Symbian support it perfectly. I guess its not high on Google's "to-do" list, which is a pretty typical thing for them to do.
You can still tether to an Android phone to an Android tablet over Wifi (in fact, I tethered my N7 to my Galaxy Nexus yesterday). However, the phone needs to run in Infrastructure mode, which is what wireless routers and access points use.
I'm not sure why your One V uses Ad-hoc though. I thought most wireless tethering apps and such now use Infrastructure mode. I mean, back in 2010 when I had my Droid Eris, it used Infrastructure mode. Granted, I needed root and used "Wireless Tether for root".