..because, statistics.
To be fair (and I do believe this was pointed out on a previous article about this), Telstra are the only supplier of broadband to a lot of exchanges in regional areas that struggle to get better than ADSL 1 speeds (myself included). This is not to excuse their poor showing on the table, but merely to explain that the aggregate statistics could quite likely be skewed by the large number of low speed customers in areas not serviced by the other providers.
I'm no fan of FOXTEL, but it seems rather disingenuous to imply that Telstra's part ownership of that company is the reason for their poor download speeds, when there are other factors at play.