The one and only reason Ookla is even remotely available on the net today, is the simple fact first of all, they have the ISP insiders market flooded.
Who else knowing, would harbor a flash base script within their internal network, unless the ends outweighed the means, or likelihood of an infiltration. If your confident enough to allow this thing to live within your public network, than obviously you've got said network protected. Fair enough right? That type of ISP network protection would likely come at the cost of the consumer. If for no other reason than isolation, which is the complete antithesis of the meaning to testing throughput across networks, that at the very least represents what the intentions are for the masses taking the test.
Secondly the ISP know well the entire idea of a test being run on any high level network, is useless and nothing more than a 'feel good' item.
These tests of Ookla, should be completely isolated on a per ISP level, if they must be used at all. Of course they are useful for tech to determine if there is or not an issue between modem/ head end (or wherever these flash tests are living). No?