No. I would call this process "open source laundering".
Actually, that's kinda an issue I see with those bridges and why I'm not totally comfortable with them. Now, if the bridge is run by the people who set up the closed communication tool in the first place, that's a grey area. That makes them run an open protocol / standard with proprietary software, which is better than nothing. I'm okay with having to reach a proprietary network with some free software. Should I join an XMPP network run with a proprietary implementation that I wouldn't probably even know about it, but at least it has usable open source implementations. That's my take. I would be happier if we could just skip the Discord and use the real thing though.
But you know, I would be fine with you considering I'm not completely coherent. I'm not indeed. I have thresholds higher than those of RMS which makes me less coherent than him on this topic.