typo3/sysext/backend/Classes/Utility/BackendUtility.php defines a general hook "softRefParser_GL" to add a general softRefParser which parses every SoftReference regardless of its type. The "softRefParser_GL"-hook is undocumented and used neither in core nor in any known extension.
There are several types of SoftReferences defined:
There is a default configuration in typo3/sysext/core/Configuration/DefaultConfiguration.php mapping "softRefParser" for several types to TYPO3\CMS\Core\Database\SoftReferenceIndex. Also rtehtmlarea adds a parser for "rtehtmlarea_images".
Removing it would mean a "softRefParser_GL" hook in an extension would have to be replaced with multiple "softRefParser" hooks for each type the parser can handle instead of having one "softRefParser_GL" hook declaring "I want to parse all!". You cannot know how every possible softref has to be parsed, so registering for every type the parser knows to handle is perfectly valid.
Therefore softRefParser_GL should be deprecated in CMS 7 and removed in CMS 8.