The ethics of accepting credit for others work

Sadly it is all too common and comes down to the prevailing culture in an organization. You can speak up, but unless the culture is fixed, then my personal experience is that it does little and can upset overall team dynamics as those with mendacious intent tend to double down when challenged.

Nobody like to not be recognised for their work, mostly because it is unfair. I would speak to peers and ask whether they had experienced something similar and ask what they did about it. It would be difficult to go to my senior and ask them to credit me personally but perhaps asking them to credit 'the team' would be a better approach.Also worth considering whether this is a fight worth having. Perhaps the learning and being sure not to behave in the same way is the best win for now?

Seen this happen a lot and often it is PM or lead taking credit for junior ’hard worker’s’ achievements. It has become almost normal.
My approach is to use the elevator/water cooler/corridor pitch to let the right people know who’s actually achieving results. It is really easy. Just say: that thing (insert actual worker here) did was pretty cool wasn’t it? And back it up the the detail if needed. Never undermine or even mention the credit taker (even if asked). If you’re in the right organisation, a couple of these pitches is all it will take (4 weeks or less normally).
If it doesn’t, leave and when settled, poach the achiever.
Simple.

We are not living in perfect world. We have to accept differences of each and every person in the team and learn to move on as a team.
I would use other other opportunities to give credit to the right person, such as informal discussions Angus has already mentioned in his comments.
We have reward and recognition programs within the organisation where anyone could give credit to whoever they think deserving, with justification. I would use that as well.