I’ve just noticed this.
I do not see on what suttas this opinion is based. To my knowledge a stream entry is incapable of 6 things. Murdering his mother, his father, mudering an arahant, injuring a Buddha, creating a schism in the shanga. SN 55:40 also contadicts this perfect ethics opinion.
In my opinion, stream entry has little to do with ethics but has a lot to do with views. That is why he is called “one acomplished in view”. I have made my case better over here: How is stream entry achieved?
When trying to interpret a book, it is good to go with the general idea in the book, with the passages repeated countless times not with a single sutta taken out of context and twisted or interpreted in a way not in accordance with the rest of the canon.
Also, we see in the suttas that Non-returners poses Jhana but not once returners. That is also why stream enterers and once returners are born in sense sphere realms while non-returners in form spheres. So a once-returner does not necessarily poses perfect concentration. It is indeed possible for a once-returner to achieve jhana and take some time untill seen with wisdom that it is constructed too but that would be quite a short time between the 2 stages, maybe a couple of days. If a once-returner would poses jhana, then he would be reborn in a form sphere witch is not the case. This is also in accordance with the fact that he has not eradicated sensual desire and therefore will be reborn in a sense -sphere.