That's rather harsh.
You either need IOSA accreditation or to be fully audited for a codeshare with any major carrier, and for most, IOSA is the standard.
There is an additional process for Lufthansa Group which is a bar higher than IOSA.
And the p**s poor income from some of the connecting partners with bmi (we're talking about the mainline airline sold to BA in 2012 here) was a major problem. They needed the pax volume but didn't get sufficient income to accompany it. There is more than a grain of truth in what's being said.
The previous posters might not have the terminology bang on, but the broad outline of what they are saying is a fair reflection of reality.