That was according to BrianGate on Gateworld who has sources inside Syfy. He won't give actual names but he's always been illuminating on the inner workings. He says that for some reason BBC America and SyFy still get ridiculously good rating for TNG despite it being 20 years old. So the Sci lead in theory works for other shows but not for SGU.
Unfortunately Briangate is a proven bullshitter. I lurk on Gateworld and the Syfy forums and he gets caught at it all the time. First there were the rumour he started about MGM canning SGA and not Syfy, despite press releases from both sides refuting that. Then he claimed to have the DVD sales figures through working for Syfy, apparently not aware that the DVD sales have absolutely nothing to do with Syfy. Also, he claimed to have known that SGU would be back in March as early as January, despite claiming in February that he would be back in April. When called out on it, he went back and deleted all mention of it from him and anyone else on the Syfy boards. He simply makes things up I'm afraid and embellishes his position as nothing more than a forum mod, he's certainly no insider. In fact the only supposed 'inside' information he's ever relayed that was irrefutably true was the cancellation of Caprica, which anyone could have guessed. It could turn out he's right of course, but he's not an even remotely reliable source of info, least of all 'inside' info.
For instance back in the day it worked for Battlestar Galactica and the Stargate Series
The discussion on why the ratings are so crappy for SGU is on going and some of the things you've brought up have been on discussion carousel for the last year. The even discuss it on Gateworld Home on the articles by Darren Summer.
I was commenting on the BS assertion from Syfy that leaving the show on Friday wouldn't make any sense as it wasn't a change, yet it clearly would be, as the show would gain a 3 million viewer+ lead-in.
There is some wonder as to if the SGU SUCKS campaign may have caught the attention of Syfy as well and part of the reason for the cancelltion.
There really isn't. There are a few dozen strange individuals on an obscure website. Their influence doesn't reach beyond organizing little groups to down-rate IMDb reviews that favour of SGU, and spamming SGU articles with hate. Clearly they're not the type of person the network is going to take seriously, in fact they're probably not even aware of them. The only reason the writers are aware of them is because they spam Mallozzi's blog.