In some cases its not that simple, for example with Hibernate if you select specific columns then the object you get back won't be put in its L1 cache because its not the full object.
So in some cases its better to select the whole object by primary key because some other method would do that later anyhow and now its in the cache and will skip an extra db call.
As a reddit user it is hard to resist throwing around the quick quips that one would expect to find but really just makes the content worse.
There really is something about the HN environment that makes one take that extra moment to think things through and write a constructive argument instead of mindless jokes.
So in some cases its better to select the whole object by primary key because some other method would do that later anyhow and now its in the cache and will skip an extra db call.