The profile in question was not deleted but rather removed as a connection. Two possible reasons would be a member was confused while trying to edit or found a new source that disproved the previous source indicating the relationship. if you believe this has been done in error, contact the PM or the Project and cite your sources. I have found conflicting sources because they were not primary sources. You can also post a comment on the profile as an invitation for others to review the connection. From a genealogy perspective, it is better to not have a 6th gr grandma than the wrong gr grandma as it effects millions of genealogist in the end.