Why do functions inside the keywords list passed as arguments to if aren’t called immediately? Is this unique to if?

# example.exs
defmodule Call do
  def this(), do: IO.puts("this")
  def that(), do: IO.puts("that")
end

defmodule Example do
  def fun(keywords), do: :ok
end

IO.puts(
  Example.fun(
    [do: Call.this(), else: Call.that()]
  )
)

IO.puts(
  if(
    true,
    [do: Call.this(), else: Call.that()]
  )
)

Output from file:

$ elixir example.exs
this
that
ok
this # expected 'this' and 'that' always to be called independently of the if the boolean evaluation
ok