What do I think the reason is? Love. The Sacredness of Scripture isn’t in question and hasn’t been insulted.
Doesn’t wash, with me.
The only explanation I can think of that fits the observations is
a marked difference in levels of adoration for one vs the other.
And, in fact, RC’s seemingly minimalist perspective on Scripture has been spoken of many times, hereon.
The emotions then generated are about as excited as those from watching paint peel.
Quite different from merely asserting, quite Biblically, that Mary was not a perpetual virgin—that according to Scripture, she had other children.
THEN the emotions flare intensely.