And vice versa. Evolution is objectively true and has been demonstrated time and time again. You just refuse to accept it because your closed minded cult tells you that you mustn't. You think that you're contending for the faith but in fact you're just brain-washed.
The endorsement of beliefs is sometimes informed by a perceived utility of the underlying concepts: if something seems useful it is more likely to be accepted. A rejection of macroevolution may come from a perception that it has no utility for predicting future events. If a species of dog further speciates, each new species is still going to be a type of dog (each of which will also have some potential for interbreeding naturally or by medical intervention). It would be simple enough to dismiss speciation as evidence of macroevolution and from there satisfactorily fit speciation observations into a microevolution interpretation.
The rejection of ideas is sometimes driven by cognitive dissonance and ambiguity aversion: the presence of internal mental friction and/or blank spaces in a concept landscape are uncomfortable and avoided by the mind where possible. A literal interpretation of the Genesis creation story is incompatible with the interpretation that all species came from a common lifeform over billions of years. A figurative interpretation of the creation story can be compatible with the concept of all life coming from a common ancestor, but accepting the possibility of a figurative creation story can leave some uncomfortable ambiguity for how other parts of scripture may be interpreted (we tend to also shy away from ambiguity). A literal interpetaton of scripture may also be tied to a feeling or reverence for a teacher one respects. If a person's parents taught them that the creation story is literal, asking them to reject the literal interpetaton is also in a sense asking them to reject their parents (that's a tall order at the best of time, unless we are talking about teenagers).
We should be cautious of what we declare to be objectively true, especially within the context of scientific inquiry. It is fair to say that a model is consistent with empirical observations but we should be cautious of presenting it as an "objective" truth because that might cause some confusion in the broader sense of epistemics or metaphysics. That, and some science is more speculative than others. In the case of speciation from a universally common ancestor, the speculation is based on a backward projection of trends we see currently and additionally assuming that no other factors or mechanisms were in play. It's the same with the Big Bang, the theory relies on the assumption that only the mechanisms in play currently (that are empirically measurable) were ever in play, and creates a backward projection based on current observable trends up to an irreducible complexity within that backward projection (the limit of the curve, approaching negative infinity). These fields of science are more speculative than say chemical science needed to make rubber or rocket fuel. One could accept practical fields of science while rejecting the more speculative fields of science that can't be tested through experimental control. If the conditions of the experiment can't be controlled and repeated, we have likely exited practical science and entered speculative science. Scientific determinations are also going to be more trusted if the end user has the ability to test it out for themselves. Boiling water at different pressures and temperatures is something anyone can do with modern tech and means. Running LHC physics experiments to search for the Higgs Boson and the omnipresent Higgs Field is basically something the common person would have to take someone's word on and is therefore subject to the same scrutiny that would be given to any politician that can be bought, bribed, or blackmailed in order to sway what they state publically.
There is a lot to think about in terms of why a person might hold a firm conviction in their position or rejection of a position. I don't see the rejection of speciation from a universally common ancestor to be a significant danger to science. But certainly we should bring awareness to the fact that such a model does not necessarily contradict scripture and by that the rejection on the basis of scripture is invalid. The topic then moves to the merits and demerits of a literal vs. figurative interpretation of the creation stories. There is usually so much focus on combatting atheistic evolution models that theistic evolution models are often completely overlooked. I think this always comes back to a conversation about scripture.
I think we all help each other out by building perspective together. I think sometimes the right eye and left eye see differently despite looking at the same thing, but through the perspective of both more depth on the subject is fleshed out. And when you think about it, there's not a single unintelligent person on these threads. Even when some rounds of insult ping-pong occasionally make a mess in the heat of the moment, I still have to admire that each of us comes from a long line of intelligent, thoughtful winners leading all the way back through our ancestors and by the grace of God we are here today. Even for those just reading without posting, each of us on these threads had enough passion, patience, intelligence and love in our hearts to wade through each other's comments in hope of gaining, building and contributing perspective.