'Dakka' is doing nothing of the sort. Some members of the Dakka community are arguing this, due to someone starting the topic in an effort to make a point.
It's not the first time this discussion had played out, and Dakka isn't the only forum it's played out on. It's usually not an actual attempt to discredit conversions, but rather an attempt to address
MFA specifically.
But I think all of the usual arguments have been made, and it's not likely to go anywhere productive at this point..