You are right that U-233 can be used in a nuclear weapon.
However you are wrong that thorium reactors breed pure U-233. It actually breeds U-233 contaminated with U-232, which is almost impossible to separate from U-233 and which further decays to hard gamma emitters, which are both easy to detect, and hard to work with. A fact which they actually saw when they did the test with U-233 bombs you mentioned.
It is much easier, and more efficient, to either enrich uranium ore to get U-235, or breed U-238 into plutonium-239.
From Wikipedia there has been only 3 tests with nuclear bombs which used U-233, of which only 1 was actually a U-233 bomb, the other 2 used a mix of U-233 and U-235 or plutonium.
In fact, to enrich U-235 you don't even need a nuclear reactor, just ore and some centrifuges.