You could say it was all of humankind's fault.

Walter Lord stated that the message of Tianic is her legacy of
"if onlys"

if only she had enough lifeboats
if only her compartments were higher
if only the Californian came to help
if only the Carpathia was nearer
if only they had sighted the iceberg sooner
if only she had slowed down
if only the captain recieved the last iceberg message

and so on, and so on, and so on.......

These "if onlys" apply to many different people in the story .