However, I hope you might agreed that bamboo fibre in its natural form has certain anti-microbial properties.
I’ve never come across a garment made of bamboo fibre ‘in its natural from’, only viscose labelled as bamboo, so I can’t really comment.
What labelling viscose as bamboo has achieved (all be it through a marketing bullshitter exercise) is made viscose clothing available to blokes, it was always more of a ladies wear material. It does indeed make nice socks and quite nice tshirts but its massively over-charged for given that viscose is more typically used as cheap substitute/filler for cotton