There's the semi-ethical issue that some adhere to.
I don't see any ethical issue at all in bot puzzle competition.
I think it even bring more interest to just plain puzzle solving.
All resources about this puzzle have information about this mempool issue.
If solver is just stupid or lazy to read more info, this is his problem.
This is the kind of reasoning used by those who say, "I'm not a thief for stealing his wallet; it's not my fault that the fool fell asleep with his wallet in his hand"
Obviously, it's unethical and immoral.
It's like breaking into a friend's house, seeing his seed, and stealing it, then saying he should have been more careful.
Now that it has no legal implications, that is something else.