So why think English can't "happily" take in, for example, the Japanese go terms. Why would it be harder for English to absorb those than "tsunami", "typhoon", "tycoon", etc.
I don't think anyone here is arguing about the ability of English speakers to absorb loan words per se.
The debate, it seems to me, is about three aspects:
1. The degree of the learning load. Dumping a big load of new Japanese terms on an unsuspecting reader was a strategy used in early Ishi Press books, and has been constantly and heavily criticised ever since. Market forces prevailed, and the style has changed. Similarly, if I were to present something to you along the lines of "seriai is an important aspect of semenogo and is one of the commonest features of the chubansen, but the thrill of the chase can be deceptive - the result is often semekirenai", I have no doubt that you could eventually learn all these doubts, but somehow I don't think I'd be doing you or our European friends any favours.
My impression is that for most established players the problem has already been solved in the form of a compromise list along the lines presented by uberdude. There may be debate about inclusion or omission of some terms, but this is small scale.
How many of those words you retain for beginners is a separate question. I rarely teach beginners so it's not something I have a strong view on.
2. Whether the terms are used correctly. I tend to harp on this topic but I recognise others find it a sideshow (their loss, I feel, but ...). Absorbing loan words with a meaning different from that in the original language is rather common, but the debate in go has to be whether this matters or not. E.g. does it matter that many English speakers think a yose-ko has something to do with the endgame?
3. Use of terms for showing off rather than communicating technical information - e.g. goban, kifu, moku. Different people have different lists and it seems that most people deprecate the practice - the debate is to what degree it matters. Does it make the game more or less palatable to newcomers?
There are other possible aspects, but some of them I regard as red herrings. For example, the alleged benefit of using Japanese as a lingua franca among westerners. In practice I can't see any significant benefit. If a Turkish guy uses shicho instead of the Turkish word for ladder, how does that help me? I need to know what he is saying about the ladder. But if I know enough Turkish to know that, then presumably I would also know the Turkish word for ladder.
Lingua francas are fascinating things. We would all readily think of the example of Latin, or French in diplomacy, and pidgin comes to mind. but in most cultures the written language of a nation is also often a form of lingua franca uniting people who speak often disparate dialects. What all these forms have in common, however, is that the lingua franca is learnt as a complete second language. It is not a mish-mash of a few foreign terms - a vocabulary list with no grammar, which is the idea often touted for go.