So I recently watched this video:
There are a couple of things I would like to say in response, some positive and some negative.
First of all, MacArthur here is suffering from a confusion of terms. When he is responding to what the Catholic apologist and Pope said, and then goes on to define Inclusivism, what he actually defines is what is known as Pluralism. Pluralism is that doctrine which states that what one believes is irrelevant, but only how one acts or whether one is spiritually connected with God.
In this, I completely share in MacArthur's criticism. Truth matters. Pluralism fundamentally denies that there is any true gain in properly identifying and submitting to the one true God. Instead, it focuses on the individual's authenticity of belief and honesty. I do not think this is biblically defensible, nor do I think it is intellectually honest.
However, by calling this Inclusivism, he is able to avoid dealing with the claims of actual Inclusivism. We see this when he quotes the obviously Inclusivist quote from Billy Graham. MacArthur's primary argument against Graham's position is merely a guilt by association. But not only is such an argument fallacious on its face, but in this case the association itself is merely artificial.
Part of the problem of course is the actual definition of Inclusivism. Inclusivism is the belief that God will take into account the conditions and situations around those ignorant of the truth, and will judge them according. You may note a degree of vagueness in that definition. The reason for that is that Inclusivism is actually quite varied in its application, and often maintains a degree of mystery about how things work in regards to the ignorant. This variety makes it quite difficult to assess Inclusivism as a whole since some forms of it can border on Pluralism, while other forms of it border on MacArthur's own Exclusivism (that only those with full understanding of the gospel will be ultimately saved). Indeed, one can argue that unlike Pluralism or Exclusivism, Inclusivism isn't really a doctrine but an umbrella term for all those nuanced beliefs that fall between the two.
As such, it is easy for someone at the end of the spectrum, such as MacArthur, to conclude that all those who disagree with him basically believe the same thing. Indeed, this seems to be the only kind of argument MacArthur seems to know sometimes. However, it is also an erroneous conclusion.