Why do spam folders show up

From the Mail>Help window

Use Smart Mailboxes to organize messages

A Smart Mailbox displays messages that are stored in other mailboxes and that meet certain criteria you specify. For example, a Smart Mailbox could include all the messages you receive about a specific project, regardless of which mailboxes the messages are stored in.

Open Mail for me

• Create a Smart Mailbox: Choose Mailbox > New Smart Mailbox. Use the pop-up menus and text fields to define the criteria for the mailbox, then click OK.
• Display Smart Mailboxes: In the Mail sidebar, move the pointer over the Smart Mailboxes section (shown only if you create at least one Smart Mailbox), then click Show. Mail provides a default Smart Mailbox named Today, which shows messages viewed during the current day.
• Edit a Smart Mailbox: Select the Smart Mailbox in the Mail sidebar, choose Mailbox > Edit Smart Mailbox, then change the criteria.
• Create a Smart Mailbox folder: Choose Mailbox > New Smart Mailbox Folder, enter a name, then click OK. When you view a Smart Mailbox folder, messages in all of the Smart Mailboxes the folder contains are shown.
• Move Smart Mailboxes into a Smart Mailbox folder: Drag the Smart Mailbox into the folder.
• Copy a Smart Mailbox: Select the Smart Mailbox in the Mail sidebar, then choose Mailbox > Duplicate Smart Mailbox. The new duplicate includes the emails that are in the original.
• Delete a Smart Mailbox: Select the Smart Mailbox in the Mail sidebar, then choose Mailbox > Delete Mailbox. The messages that were displayed in the Smart Mailbox aren’t deleted.

If you change a message in a Smart Mailbox—such as marking the message as read or unread, or moving or deleting the message—the change is reflected in the mailbox where the message is stored.

If you use iCloud Drive, your Smart Mailboxes are available on your other Mac computers that have iCloud Drive turned on. For more information, see Store your desktop and documents in iCloud.

See alsoCreate or delete mailboxesRename mailboxesUse rules to manage your inbox

Do you really have that many accounts?

They appear to be the the Spam folders for the individual accounts, and you have the individual accounts set to store Junk on the local mail folders instead of the account server Spam folder (Mailbox Behaviors).

If that is all same account, you are not using the server spam folder but some obscure Junk folder inside your Inbox. Nobody but Apple calls it Junk, so I assume you created that folder yourself. Since you are not unifying the server spam folder, it is showing up under that account, just like any other unattributed server folder.