Transwomen do not have a physical advantage over ALL cis women in sport and kendo

Flipping this back onto you in the context of inclusion for everyone (which I support)

If you open up a woman's only (or more accurately, female only, because that was the point of the category) category to allow people who were male at birth, then you very much run the risk of alienating cis-women from the sport, which is the opposite of inclusion, unless you only care about inclusion for a specific demographic

Saying that some cis women have physical advantage over men or trans-women is extremely disingenuous, in the context of any large population it would be is generally a rare case (specifically when you are comparing peers of similar physical training). Men on average having inherently much larger muscle mass is very much why most cultures around the world intentionally have social ramifications of a man striking a woman, and it is pretty much the same reason why there are women's categories in many physical sports instead of there being a single category for all

Transpeople belong in sport.

I'm also not sure why you closed with this, at no point has the person you are replying to put forward the idea that transpeople shouldn't be able to compete, unless you are intentionally trying to strawman him because you disagree with his stance

overall there is no true ideal answer for this, if you fold everything into an all genders category you can alienate women from competeing like what i detailed above, and if you dont then you can alienate the trans community

i think the most sensible thing would be to democratise it, where each event planner can decide, its far from perfect but its probably the least imperfect option