What is the practical difference between the training someone
receives in a PhD program verses a masters?
In one sentence, experience with planning and conducting scientific research in a particular subject domain.
A Master's degree may be viewed as an fast-track apprenticeship program. If done right, it allows the apprentice to get their feet wet in a knowledge domain, try out a relatively small-scale, "practice" project of independent research, and get oriented in the general space and culture of graduate-level academic (or "serious" professional, as in applied fields like business) life and work through a 1-2 year period of focused study.
In comparison, a PhD is a substantial, systematic program of study with a duration, structure, and checks and balances intended to make it difficult to cut corners, and instead to fully invest one's intellect in training of research in a particular knowledge domain.
This is a big area though, encompassing a fairly long laundry list of competencies, from subject matter knowledge (including past research, currest state the art, and future prospects), analytical thinking (both in the intricacies of the subject matter as well as practical issues of how to formulate, address, and communicate findings related to questions answering which is of value to the field and hopefully society at large).
At the end of the day, as has been pointed out, both are types of vocational training intended to provide a foundation upon which one might build themselves to become a professional in a particular area.
In some sense, both Masters and PhD are indicators of commitment to a particular occupation. It is relatively easy to try something out for a year or two, requiring some but not a very large amount of commitment, time, and effort.
It is relatively more difficult to do this for an extended period of time (typically 5-6 years) and invest oneself fully into a large, long-term research project where much time-on-task is expected and personal discipline, perseverance, and abilities to overcome challenges and make a recognized contribution to a field are put to the test.
The practical difference is that a person with a PhD would be expected, ideally, to be that much more effective in doing these kinds of things and exhibiting these types of qualifies as applied to a research-intensive occupation, all other things being equal. That is the working assumption, and the 'why' in 'why do a PhD'.
Why should I be willing to rank a PhD higher given the same amount of
time in field?
Whether you are willing to rank a PhD above MA/MS depends on the value you attribute to the practical difference between the two (previous question). If these differences are relevant to your concerns, then you will probably interpret a PhD as carrying more 'weight' in terms of these relevant characteristics. So to some extent it is a matter of personal perspective. Also to some extent, you may want to defer to the "institutional culture" in ranking a PhD higher if your personal perspective aligns with that culture (stated differently, if you subscribe to the same premises).
One example of this is if you consider yourself sharing the cultural norms which exist in certain settings, of valuing greater ability in academic writing, experience conducting scholarly / scientific research (e.g. selecting appropriate methodology, planning/conducting the study, acknowledging methodological limitations, and clearly writing up the background/method/results/discussion).
What it boils down to, in my opinion, is the assumption that experience equals ability. The practical purpose for earning a PhD is formally engaging in a multi-year program of professional development with the assumption that it will yield greater skills/knowledge (ability) in a particular subject domain, as well as in some transferable skill areas such as research competency, as in the example above.
What's the difference between a masters and a doctoral degree? (see paragraphs "Purpose and uses of a doctorate" and "Purposes and uses of a masters degree".
More focused discussion in reference to computer science
A related question on Academia
Hope this helps. Good luck!