Here is the main reason why.
The first is a classic case of what a lot of people feared from the March for (intersectional) Science - the community would be heavily divided, bifurcating along creedal lines. One camp values the pursuit of cold objectivity, the other values embracing intersectionality and "equitable" outcomes.
(By the way Tara Smith is an associate professor of infectious diseases and so is certainly aware of many scientific process debates. She was also up on Science Blogs.)
Like most things, there's value to both teloses. I'd suggest the intersectional camp facilitates religious like dynamics more than the objective camp, but as the New Atheists showed, quasi-religious dynamics never go away. Once groups coalesce, the chances of them stumbling into adaptive group resonances and then into quasi-religious dynamics increase.
What's the danger? "We don't debate hate speech and hate facts!" It's the inevitable polarization that (stochastically) occurs once you remove the boundaries against decohering polarization. Only certain experts are allowed to moralize.
Because morality is usually dogmatic, debates tend to utilitarianism. However, the utilitarianism is tribalized. It is not what is "good" for all (at least directly), it is what is primarily good for identifiable groups which is secondarily assumed to be good for all. Identity politics rears its cancerous head, and while I may be naive, it seems that marginalization of "privilege" based on identifiable characteristics is inevitable. This sets the stage for severe group competition.
While acquiescence is certainly possible, it is very unlikely except in certain exploratory groups who are playing the odds that loss of individual fitness will be offset by gains emerging from group-oriented altruism. But the only way to protect the group from cancerous within-group competition via identification (oppression olympics) ad infinitum is to have some very strong boundary norms about where divineness stops. Hence the value of clear confessional statements and strong in-group out-group gradients (via norms, costly commitment displays, shared rituals, behavioural/dress demarkers, etc.).
So why do I hate creedal statements in academia? Because I am very tempted to support the Shermer approach to science, sign what ever creedal statement they eventually come up with and start sticking it to all those medieval retrogrades! You see, if we position it so that intersectionality is a sin as egregious as modern racism, because, well it is classically racist, and our side is sure these acts will decohere society as much as any well-intentioned political communism ever could, then I'd be fully justified.
So why not just let the issues of intersectionality stay under the cover and ignore them? For me, ignoring problems is just stupid. But formalizing them in a way that invites their resonance (by some) into weaponized inter-group competition weapons is equally silly.
Listen to voices and deal with issues at a personal rather than group level. Group dynamics, especially around moral issues are very different from what happens at the individual level.
I fear Western society will re-learn this "fact" as society continues to bifurcate between the quasi-religious political left (ctrl-left) and the far / alt-right.