Surely it cannot be any more questionable than 'Tintin in the Congo'?
Not necessarily - but it only needs to be as
questionable - and actually The Secret Ray
may be in some ways more so. It again comes down to Hergé depicting some island natives in a simplistic and patronising fashion, which is as you suggest, dated. We should also remember that “dated” doesn’t actually mean “old, but no longer offensive”: as has been shown by recent activity, such as court cases to have the books withdrawn, Hergé’s depiction of race is still something that offends and upsets many people, and we may perhaps have to temper our thirst for his work if it has the power to hurt people.
As to the publisher “simply” doing something, the controversy surrounding Congo
should demonstrate that nothing in these cases is simple. Methuen did not want to court controversy, so they delayed the release of Blue Lotus
until they felt that the market would accept it, and chose not to do anything with Congo
and The Secret Ray
When Egmont took on the works, they decided that they would
out, but by that time Secret Ray
had been placed elsewhere, so it isn’t part of their series, even if they wanted it to be.
There is introductory material in the book as it stands, and it is available if you look for it, so I’m not sure what you are questioning, exactly.