Because as we have already discussed the fact that all scammed people are outside of this forum. Noone (from old users, who have money to gamble) on this forum is using their services.
Or, at least, their efficiency is too low for such amount of paid sig spammers (this is like 100 % I think)
All scammed victims are definitely not from outside the forum. Majority of them are, but minority are forum members who most probably aren't coming forward in order to avoid humiliation which makes sense.
I am not up-to-date if there are new scam accusations posted here regarding 1xbit, but I believe there were users here that became their victim who are still active until today. Just guessing.
Agreed. Which Bitcointalk member would want to inform other members that they got scammed by 1xbit? Very few is the answer.