Since we got a new feature to prevent sorting by modified date I think the better option would be to prevent likes from pushing items to top. In my opinion a like is not enough to move a stream item to top again. A comment on the other hand is content for other users to react to again. Therefor I think this way would make more sense.

Thanks to Mark for providing a temporary solution by commenting out line 961 in /administrator/components/com_easysocial/includes/likes/likes.php:

Replace this:

$stream->updateModified($streamId, $this->my->id, SOCIAL_STREAM_LAST_ACTION_LIKE);

with this:

// $stream->updateModified($streamId, $this->my->id, SOCIAL_STREAM_LAST_ACTION_LIKE);