That's correct - at this time, we don't have a bulk method of adding records to the clipboard.
However, if it's search results you are after, AtoM does have a separate export for search/browse results in CSV form, for authenticated users. See:
Keep in mind that the search results export will not include associated descendants (i.e. if a collection is in the search results, the child records will not necessarily be included, unless they are also in the search results). It also won't group the export results by parent so that the CSV can be easily re-imported - instead, the order will depend on the order of the search results, so depending on the search terms and results, a child record may appear in a row higher than a parent record (or the parent record might not be included at all). Because of this, I wouldn't say it's a great way to export data with the intention of re-importing it, unless you are working with discrete items, or intend to review and clean up the exported CSV (i.e. reordering it, checking parent relationships, etc).
In the meantime, the clipboard export does allow you to include descendants, so it's not necessarily to individually pin every record in your system - just the top-level descriptions.
It would be great to be able to have a "select all" option for pinning to the clipboard at the top of a search results page! Something for the future, perhaps :)