In honesty I didn't hear all his statements back then. Now from a quick search I can only find his Twitter:

„Natürlich kann es so gewesen sein, wie es @derspiegel annimmt. Es kann aber auch anders gewesen sein. Ich habe als Rechtsanwalt häufig erlebt, dass alles gegen A sprach, es war dann aber doch B.“

Which just says there should be more investigation before accusations are made. Asking for evidence. If you have a link to an interview or talk where he does as you said I would be interested to hear how he phrased it.

I want to point out one thing I have seen far to often in recent times: If a person or group of the left make a wrong statement others which previously followed them are quick to change their view and declare them as persona non grata. On the other hand we have the far right which spills out lies after lies and their followers are so used to it that even disproving them in multiple points does not touch their loyality in any way. I think we should focus more on welcoming people who try to do good thing. If they make a wrong step we should not shun them but try to show them why they did wrong. At least hey try to better themselves and you/we have a good chance to convince them of the better way.

See for example Snowden. He made the mistake to believe Russia would never invade Ukraine. An easy mistake if you have to live inside Russia propaganda machine. Upon realizing his error he was so struck by it, because he uses his social media reach to better the world and now trough a mistake he abused it for spreading propaganda, that he apologized and stopped tweeting for many months.