Why are permissions required for verifying Mastodon accounts?

[FediVideos]

The current linking to Mastodon asks for "Full access to your Mastodon account", which is sort of scary and it isn't clear why this access is required.

You can verify your Mastodon account ownership on other sites in both directions using the rel=me attritbute without granting any access. Why isn't this used for verifying ownership of Mastodon accounts?

[FediVideos]

Oops, looks like duplicate of #2149