He self-identified as a conservative.
Sander's policies are strongly liberal socialist.
This is a no-brainer. This would be like having to explain why a liberal finds disfavor with Trump's policies.
[general soapboxing]
Personally, I tend to think of myself as an independent centrist (†), unaligned with any party. That said, I see the mainstream DNC as being a bunch of panderers that talk a good game about the economic status of large demographics of our country, but then do a whole lot of nothing in the legislature, even when they have the necessary majority AND a sympathetic president, and SHOULD have been able to enact such reforms. I take this as being symptomatic of a political group that leverages the existence of an underclass as a means to remain electable; Sort of like a doctor that manages pain, instead of treating its cause, because he gets kickbacks from the drug manufacturers. I consider this abhorrent, and not what an actual public servant should be doing. (In either case.) Granted, this is the "worst case" scenario; A fair number probably just suffer from learned helplessness from all the years where they were deadlocked with the GOP, and so were unable (psychologically) to put forward or support the sweeping changes that have been sorely needed for decades. In either case, the need to remove them, and replace them with actual movers and shakers is sorely apparent.
Likewise, I view the mainstream GOP as transparently obvious examples of quid pro quo between government and large financial and business interests, often with direct stakes involved (being large stake shareholders in such institutions.) They promulgate a false narrative(*) about what capitalism (as a system) is supposed to look like, because that false narrative is what ensures their financial and political power structure. That it is so obvious, and people so oblivious to its obviousness, makes me die a little inside every time they get away with it. Needless to say, I feel they need to be removed from power with maximal prejudice.
The "new generation" democrats however, strike me as people who are not hypocrites in regard to their rhetoric about the poor, and actually want to enact actual policies (Shock, HORROR!) that would cost money for the wealthy (EGADS!), and would result in a restoration of the derelict communal infrastructures of the country (UNTHINKABLE!), and are unwilling to roll over for their mainstream "old guard" peers.
This country has not seen this kind of liberalism for over 75 years, and does not know what to do with it. Personally, I am totally down with getting new infrastructure with government subsidies, like we did with the interstate highway system (A product of "busywork" created by the NewDeal economic policies of FDR), and with getting modernized healthcare regulations (Like the rest of the developed world). To me, its absolutely obvious that this will cost a great deal of money, but it is also absolutely obvious that the total benefits to the society at large will be much greater than this cost. The issue is that the channel of communication is dominated by those with the most to lose, (Since they do not profit much from improving the social norms of the country at large), and so false stories of "SOCIALISM!!" (in the Red Menace sense(+)) get spread around with fat brushes to scare the public into making decisions that are counter to their actual interests. (Because actually fixing social inequality gets rid of the mainstream DNC's meal ticket, and actually fixing social inequality will result in reduced profits for GOP stakeholders).
Sanders, Warren, and co. have been staunchly in the "Actually DO something!" category for YEARS. They are just now getting to have a platform, and it's about fucking time.
I would be happier with younger candidates too, but saying that they are hypocrites is just unfounded.
(†) Centrist, in that I view a balance between liberalism and conservatism to be the ideal state. It is indeed entirely possible to be so liberal and tax happy to fund such antics, that people cannot succeed. However our CURRENT status is SO EXTREMELY FAR to the right, that policies that are rightfully seen as radically left are absolutely needed to reach this center. I reject modern "moderates", as they are not actually center. They are just "not so far in the Right-wing"; a position that keeps getting dragged further and further to the right by more and more radical conservatism.
(*) Capitalism, as a system, is predicated on the supposition that the market is comprised of many small actors, all constrained by public consumption patterns, to provide the maximally productive and highest quality products at the lowest pricepoints. However, this is not the system that is being supported by the GOP, which is instead an oligopoly; A system dominated by a handful of massive players that dictate consumer behaviors, mandate and fix price points, abuse their dominant positions to provide inferior quality products and services, and which distort government through "lobbying", "political donations", and the offers of cooshy positions for tractable politicians. The GOP pretends this latter system is "Capitalism." It's not.
(+) There is purposeful misrepresentation of "liberal socialism" (more modernly, "Euro-socialism") with "marxist socialism" and "Soviet socialism". This is done purely for political reasons by people who really DO know better, but profit from the combination of ignorance and information overload in the public, to engineer a more favorable narrative that keeps the disruptors out of power by deplatforming them.