exactly
the ad networks are just middle men really providing a service between advertisers and publishers. if publishers dont like the ads showing through the network then they are free to stop using them.
if you expect coinad/coinzilla/a-ads/cointraffic/mellow etc etc to make judgements about every advertiser that comes along, whether they are possibly a scam or not - then its really not going to work
i cant believe for a minute that they are involved in any scams
the simplest explanation is usually the correct one - the owners of these investment programs probably just use the ad networks themselves to directly promote their service