In the Collection#with method, only 4 options are allowed to get changed:

CHANGEABLE_OPTIONS = [ :read, :read_concern, :write, :write_concern ]

Now, write is a deprecated option that is equivalent to write_concern, and I think whoever wrote these options believed that read is a deprecated option equivalent to read_concern. Unfortunately, it seems that this is not true. I have found that whenever read is used, the mode option is used, which is a read_preference option. Additionally I found the following docstring:

# @option options [ Hash ] :read The read preference options. The hash
#   may have the following items:
#   - *:mode* -- read preference specified as a symbol; valid values are
#     *:primary*, *:primary_preferred*, *:secondary*, *:secondary_preferred*
#     and *:nearest*.
#   - *:tag_sets* -- an array of hashes.
#   - *:local_threshold*.

which pretty explicitly states that read is a read preference option.

Additionally this code snipped implies that read and read_preference are equivalent: https://github.com/mongodb/mongo-ruby-driver/blob/master/lib/mongo/collection.rb#L168-L170

The docstring for #with also says the following:

Provides a new collection with either a new read preference or new write concern merged over the existing read preference / write concern.

So the CHANGEABLE_OPTIONS are clearly wrong, and the read_concern should be replaced with read_preference.