Again, it depends on what you mean by "easier." Let me put this into perspective. The ratio of interviewed applicants to total number of applicants is roughly similar. For example, at UCSF (a very competitive program), around 60 interview invitations are given out among the 400 or so applicants (~15%) for MD/PhD. For MD, it is about 500/5000 or ~10% (note that the latter figure includes both MD and MD/PhD applicants). Yes, you can say that it is "easier" to get an interview because a greater ratio of applicants gets interviewed for MD/PhD compared to MD. However, this would be very misleading. The average MCATs, GPAs, and amount of research experience are significantly higher for MD/PhD applicants, making even getting an interview at least as competitive as MD, if not more so.
Furthermore, the class size for MD/PhD is very small compared to that of the MD program. The acceptance rate for MD/PhD is the same or lower than for MD, but not higher.
The bottom line is that the MD/PhD pathway should not be looked at as a backdoor to MD admissions. Given that interviewers are highly attuned to picking up on that sort of thing, I would not recommend applying MD/PhD unless you are extremely motivated and have a strong interest in both medicine and science.