The article lists several reasons why the regimen is dangerous: if you get the bacteria that you're supposed to be getting, that bacteria will be continuously producing an antibiotic. Having bacteria constantly dosing you with antibiotics can lead to all the sorts of issues that long-term antibiotics present. Secondly, the article claims, probiotic manufacturing is very susceptible to contamination. Luckily, there are steps a manufacturer can take to avoid contamination, but it doesn't appear that this manufacturer is taking these steps.

All of this is stated in the article, if you missed this on your first read, you might consider re-reading it :)