A popular discussion (and I think a poorly-developed idea) that is wending its way through vegetarian e-mail discussion venues asks:
Does worldview condition our likelihood of reverencing the personhood of other species?
This idea has been made into books (as in An Unnatural Order: Why We Are Destroying The Planet and Each Other by Jim Mason and Peter Singer, 2005), where (in 'feminist' style, Mason and Singer claim that theism is hierarchical, while naturalism is not; hierarchical approaches to nature oppress animals and women; therefore, justice must abolish both in one fell swoop.
The issue has been approached a number of ways critically. In The Spectre of Speciesism, Paul Waldau asks whether Buddhism has a better historical record on animals than the monotheistic Abrahamic religions; he concludes that they do not.
In one blog, it was asked (somewhat 'inelegantly'):
VeggieTart (one of the early respondents) offered a succinct and excellent response, demonstrating that worldview, while possibly correlated in individuals, is not an automatic determinant of one's understanding of the ethical issues that make one an ethical vegan.
A secular approach that is not antagonist to religious or theistic worldviews is Ethical Culture (inspired and founded by Kantian Felix Adler in the 19th century), which teaches (www.AEU.org) that ethics is autonomous (independent of religious worldview) - that is, one does have enough rational capacity (natural reason, inner 'light', etc.) to reach stable and sustainable moral conclusions without reaching agreement or final understanding of religious truth (or error).
Ethical vegans should be as astute as Adler and his followers.
So, on the question of whether the TYPE of worldview influences the adherents' approach to the personhood of other species, surely it does, but not always in black-and-white, either-or ways. A better approach, I suggest, would be that of comparative religionists that asks each student to explore this question in depth; if only superficial analyses are offered, lower grades are assigned.
So, look deep, dig deeply, and ask the question of whether or not there could be insight and justice for animals in EACH of the intellectual outlook options on ultimate questions. That's precisely my long-term point. And again, ethical vegans who really DO NOT KNOW one way or the other on ultimate questions should be as astute as Adler and his followers. Otherwise, THEIR ethical insights are only topical advances, not wholesale advances in ethical analysis.