[kazinator]

That point is clearly made in the comment you're replying to, with the additional point that if we are talking about C, then sizeof is an operator, not a function. It doesn't require parentheses, except when its operand is a type expression. No well-considered coding convention requires superfluous parentheses with sizeof, and there are good reasons to ban them.

We should prefer code like:

   type *ptr = malloc(sizeof *ptr);  /* no parens */

to

   type *ptr = malloc(sizeof (type));

In general it's often better to base sizeof on an ordinary expression rather than a type expression.

If we don't use superfluous parentheses on sizeof, we can then look for sizeof followed by an open parenthesis to look for code where sizeof is applied to a type expression.

  sizeof (type)

means "produce me a size_t value based on some arbitary type, without checking that it's related to anything in the surrounding code". It can be as dangerous as a (type) cast.