Why can I only choose certain sites for migrating a question?
This question has been asked before.
Originally (6 years and 9 months ago): When voting to migrate an off-topic question, why is the list of sites limited? and Off topic questions and redirect to affiliated sites
Latest (3 years and 10 months ago): Migrating a question to another SE site
What is currently suggested as a "solution"
The latest official stance (from the original question) is:
The list of sites is limited because many people who vote to migrate do not fully understand the scope of the target site, or migrate questions that are of marginal quality, so many questions get migrated when they shouldn't be. This is further illustrated in Jeff Atwood's answer.
Moderators do have this capability. If you do not have this capability in your "close as off topic" dialog, flag the question for moderator attention, with a comment specifying which site the question should be moved to, and we will migrate it if it is appropriate to do so.
(Bold emphasis is mine)
I am trying to flag the question for moderator attention! How could it possibly be more convenient to flag a question in a jury-rigged way than to just give me the ability to flag it correctly in the first place? If for some illogical reason you don't want to give me the ability to choose any site to suggest migrating to, then why not add an option after the 5th and final choice of "Other", so it is obvious this is where I should write something in? As it is, it's complete guess as to what steps of flagging-button-presses I have to hit in order to get to an all-purpose "Other" page.