It all comes down to avoiding doing harm and leaving other beings alone (where possible) as opposed to harming or not leaving other beings alone without being real 'mean' about it, doesn't it? (beings here references living entities who are sentient)
The longer I view the world and her beings through vegan eyes, the crazier and stranger a "welfare" position seems to me. By the same token...a rights position (vegan) probably looks just as strange and crazy to an occupant of the welfare position. I don't know if it works quite that way or not...maybe it does. ("crazy" here used as a substitute for the phrase "disconnected from reality")
It is generally true that vegans...humans who take the position that whenever possible no one should harm anyone else ("anyone else" = any living sentient being)...are considered to be "crazy" or "extremists" or "wackos" by the dominant human cultural narratives. Anyone who is vegan and is reading this knows this...and...anyone who is not vegan and reading this also knows this to be an accurate description of how most human animals view those who are vegan.
But...when comparing the two stances like this:
Welfare: "Well, I'm going to use or kill you (or whatever horrible exploitative thing is being done to an Earthling) for my own purposes but I will try to do it in the least awful/painful way possible."
Vegan (honoring an Earthling's right to their own life): "I won't imprison, exploit, use or harm you. You live your life, I'll live my life."
The first one looks bizarre and insane to me...and the second one looks pretty decent. Harm or no harm...simple, right? Oops...not true.
The distance between those two positions is, in many ways, very immense...especially if you consider what must be waded through (engulfed in) to get from the first one to the second one. Guilt, shame, horror at what one has done...all these awareness invoke unsettling, painful and disturbing feelings. Yet...these are the necessary emotional working-throughs that must be accomplished to journey toward genuine comprehension and persistent implementation of ethical veganism.
Without that working-through, I fear that any "vegan" stance is simply a role, a behavior with no heart and/or substance that can be jettisoned at any time with minimal or no emotional consequences. An example might be someone who sometimes "cheats" on their vegan "diet" because "cheese tastes so good".
If someone has done their feeling/comprehending 'homework' however...then vegan is a way of being and not one of simply acting. Being vegan is a transformational process that changes not only the individual's behavior but their way of seeing and apprehending and experiencing Mother Earth and all of her children...and how those children behave.
Apprehending and appreciating and affirming that all beings are equal in
their 'right' to their own lives and to live those lives how they want (taking into consideration that all beings must co-exist together)
is a breath-taking and incredibly profound comprehension shift vs the
worldview engendered by the conventional cultural narrative about human and non-human beings. That shift, for me anyway, has changed how I see and experience so many things beyond that modest sounding phrase "concern for animals".
Going vegan is a journey involving behavior change and in how you see and experience both your inner and your outer world...and all living beings. It can't be described accurately, it has to be lived...and in the living of it not only does one begin to think and comprehend differently...one also begins to experience Mother Earth and her Earthlings (all of them) very differently. And it is a journey that doesn't end...there is no "I'm there" moment because there are (potentially) always new understandings and perceptions and behavior changes arising.