I wholeheartedly agree about the name Oswald. Thank goodness the book is written in the first person. (My condolences to any Oswalds out there.)
I think a lot of it is also the time it was written in. Oswald hates people being emotional, he has a lot of patriotic pride, etc…all traces of a Victorian upbringing.
So yeah, I see how it could be seen as offensive. I rather liked it–Eng 12 is currently bashing me over the head with all manner of feminist, anti-colonialist, politically correct rubbish so I’m feeling rebellious. 
Sort of odd to think that the Bastable boys were just about the right age to fight in WWI…