Two people buying and selling the same dollar a trillion time would hit that trade volume in a day. There's also a huge difference between short term and long term bonds.
So we need a better metric to evaluate this against. If we look at recent auctions, they typically move around 35-40 billion in 10 year notes and about 25-30 billion in 30 year notes. With the rest being short term.
In 2025, the Treasury issued $30 trillion total over 400 auctions.
So yes, $100MM is not a lot, but it's still three or so auctions worth of bonds. There's also the downstream impacts of this, as the Netherlands is likely no longer buying t-bonds in any form. And this is just one country.