Most people in bitcoinland are financial newbies, so these kinds of mistakes are common.
Perfectly understandable, but in the interests of everyone it would be better to fix those mistakes, switching securities to the correct category.
Is there a specific reason why this hasn't been done, or it's just because nobody cared or because burnside is too busy?
Well on the pass-through issue, whilst pass-throughs technically aren't stocks in many ways it makes sense to actually list them as stocks. That's because, if operated according to contract, their behaviour is going to be identical (less management fee) to if they WERE actually stocks in the underlying asset. So listing them as whatever the underlying asset is does, sort of, make sense - in terms of informing potential investors what they can expect if they invest. For this reason the three pass-throughs I run myself (on LTC-Global) are all listed as stocks despite technically being funds.
Listing funds as bonds is a far more serious error. Stocks and funds have a lot in common which is NOT shared by bonds. Fundamentally the different is that bonds are debt (if you hold a bond you are owed a predetermined amount of money) whilst stocks and funds are both equity (you own a portion of either the company or its assets). With bonds the amount owed should never change - with stocks and funds there's no defined value and what your shares/units are worth is determined by the performance of the company.
The issue is further confused because a lot of IPOs are stock-like in nature but claim not to be stocks (they explicitly state that the share do not represent ownership of the company). This is largely a (totally futile if regulatory authorities ever take an interest) effort to try to pretend they aren't securities at all but does make classifying them difficult (they give most of the worst features of all types whilst omitting those recourses which investors would otherwise have). Those haven't managed to invade BTC.CO much yet (Bitfunder has plenty of them) but probably will.
My view on it is that the classification (stock/fund/bond) should be the best fit for the behaviour investors can expect from the security - whether or not it's technically correct. Whilst there are definite grey areas between stocks/funds (the primary difference is whether you own a company or only some part of its assets) there's no such grey area with bonds.
It's not an issue burnside can just go and solve. Moving categories would just cause confusion unless, at the same time, contracts were also amended (often requiring a vote by investors). Then operators would also need to update their threads, websites etc. All of which takes time which, for many companies, could be better spent on other things - such as producing the accounts/lists of assets that many are so deficient in.