I don't know how to read this Darwin related passage.

[Kitaoka]

This is a simple grammatical question.
Please read this.


Darwin's Dangerous Idea (D.Dennett)

From the moment of the publication of Origin of Species in 1859,
Charles Darwin's fundamental idea has inspired intense reactions
ranging from ferocious condemnation to ecstatic allegiance,
sometimes tantamount to religious zeal.


The problematic part for me is
"sometimes tantamount to religious zeal.".
Is this sentence related to "intense reactions" or "ecstatic allegiance"?
I thought ecstatic allegiance is similar to religious zeal, so I read it as
"ecstatic allegiance, sometimes (being )tantamount to religious zeal."
Am I right? How do you read this?
Thank you.

[birdeen's call]

I think so too.

[riquecohen]

I think that both ferocious condemnation and ecstatic allegiance can be equated with religious zeal. Hence, in this sentence, intense reactions of whatever nature are tantamount to religious zeal.

[Kitaoka]

Thank you for your replays.
Some Japanese says there is only one interpretation in this, so I asked.
But it seems this sentence can be read in several ways.