Are these books not banned to protect the children? Should other states be allowed to circumvent and subvert protections your state offers children?
How about other countries?
To put it less confrontationally - the books are banned from schools and public libraries. They're not banned from private purchase or private ownership. You can give these books, you can gift them, you can sell them, you can loan them. Just not anywhere that's publicly funded.
So there's really no difference between them being available from Brooklyn Library and being available from Amazon. As long as Texas isn't funding the BPL, there's no issue here.
From words? Freedom of speech. So, yes.