Republican presidential candidates have to pander to the hard-right base to get through the primary. This means that they need to espouse genuine belief, or give convincing lip service to, the religious right's pet topics including but not limited to religious influence on education, creationism in schools, climate change denial, stem cell research, the anti-vaxxer movement (in fairness, many liberal hippies there too, but they
don't vote), science research budget proposals, preference for business over environmental protection dating back to the 1970s, resistance to public health initiatives to reduce STDs and unplanned pregnancies, on to the outright supervillain-worthy perversion of science to push religious agendas (such as my own state legislature's nearly-successful efforts to impose mandatory pre-abortion transvaginal ultrasounds on women).
Perhaps it would be fairer to say that it's strongly
religious people who tend to be anti-science, and the Republican party embraces and depends on that voting bloc. This is particularly true during primaries, when it's the strongly motivated party base that gets out and chooses candidates.
Meanwhile, American scientists self-identify as Democrats over Republicans
55-6. If you're going to argue that the Republican party as a whole isn't hostile to science, you need to explain that with more than the usual Republican "universities are cesspools of liberalism" reply.