I am following the notes "Introduction to Modern Cryptography" by Bellare and Rogaway, and on the chapter about blockciphers there is the following claim (page 11 of https://cseweb.ucsd.edu/~mihir/cse207/w-bc.pdf):
2DES, although having the same effective key length as 3DES2 and offering what appears to be the same or at least adequate security, is not popular in practice.
However, from what I understood, the effective length of 2DES is 57 bits, since it can be attacked by the meet-in-the-middle attack (this is stated on the end of page 10). On the other hand, the text says that 3DES2 does not appear to be target of meet-in-the-middle attacks, so its (effective) key length is 112 bits.
So I was wondering if I am missing something about these statements or if there might have been a mistake in the text (I did not find any errata).