Why is a Taylor polynomial centered around $0$ called a Maclaurin polynomial? It's only a special case of the Taylor polynomial, and it is calculated the exact same way as a Taylor polynomial centered at any number. It doesn't seem to carry the same weight as other named concepts such as Euler's number, which has special properties when you differentiate, integrate, etc.
Stigler's Law: No scientific discovery is named after its original discoverer (this was discovered by Merton).
It's called a Maclaurin series because Colin Maclaurin made extensive use of them to make advancements in the field of geometry. He also covered this case of Taylor series extensively in his treatise of fluxions.
If you want a really unfair example, you should see l'Hôpital's rule. This rule was discovered by Johann Bernoulli but it is named l'Hôpital's rule because a guy called Guillaume de l'Hôpital published it in his book on differential calculus.