I guess in combining lactivism with my friends, my most open lactivism is when a friend is pregnant - I will send an email out with a list of good books for while she's pregnant (or while his wife is pregnant), for baby time, and a separate list of breastfeeding books on the list too. I am a bit of a wonk and my friends know I like to research stuff, so I think most of them realize that these were the best books I found on the subject, and that I'm trying to save them time finding good books themselves. That's the way I approach it, anyway.
I also sometimes will mention that we had some rough times breastfeeding dd1, and that we're up late and more than happy to talk through struggles they might have; I suggest LLL meetings before baby arrives.
....That said, SIL weaned her preemie at 4 months. And didn't tell us for another three months. And I have friends who've bf'd for varying lengths of time ... many of them make it a year (or nearly a year); a couple close friends have nursed past a year with my example and encouragement, with their second babies. One, nursed her first two years and weaned her second promptly at a year (because she thought it would be easier to wean then, than otherwise). I know I've got some friends who've ff'd from the beginning, or nearly the beginning ... one due to a medication (and I think poor MD advice) and others, I'm not sure why and haven't asked.
In terms of the judgmentalism issue .... For whatever reason, I seem to come across as judgmental. For people who've done personality tests, I am a "Green" in the Colors test, and in Meyers-Briggs I'm an ESTJ - which can come across as judgemental, but isn't really. I am just a very analytical person, and I do like to discuss/argue things too sometimes. I think those who know me well, know that I'm open-minded. My professional career has been mostly in a supervisory, HR type position with lots of interaction with people so it's an area I've worked on for a long time but that perception I think can still be out there for me.
So .... while I try not to judge (and mostly just feel sad for the moms and babies who weren't able to breastfeed, for whatever reason/barrier they encountered) - I know that some people may infer a judgment that I've never spoken and likely never thought. There's that "guilt" which sometimes gets externalized and placed on others .... Add to that, the fact that we dealt with some serious supply issues, FTT, multiple food allergies and a strict ED with dd1 and a strict ED with SJ too, and I think that whether I think it or not, people who've quit breastfeeding might assume that I'm judging them.
I can't control, though, what other people assume. All I can do is try to moderate my own statements and interactions so that I don't come across as "judgmental."
I try to stress that any breastmilk is good; that there are a lot of barriers against successful breastfeeding .... To ask for help, and that it's worth it. And I try to give "mad props" to moms who are breastfeeding (especially if they've had struggles). But in the end, even complimenting a mother for managing to negotiate a pumping schedule with her work, could be inferred to be a judgment of a mother who wasn't able to or chose not to, KWIM?
Where I really struggle, in breastfeeding conversations/discussions, is when the other person begins the conversation defensively from the beginning. When they are already defensive, it's hard to disarm them enough to support them for what they accomplished, while still kindly providing good information if they got lousy information/advice. This has only happened to me with my sister ... but it's a rough conversation to negotiate.
For me, the issue is larger than the individual experience - breastfeeding and breastmilk is best for mothers and their babies. Backed by every study ever conducted on the issue, every medical group, etc. But there are huge social barriers to successful breastfeeding, whether via our health care system, or employment, or social support systems .... Trying to bring the focus to the big picture, and to overall support for breastfeeding and why it's that important, regardless of whether the person I'm talking with was breastfed, had breastfed children [for whatever amount of time], or etc. There are lots of individual reasons that breastfeeding (or its duration) doesn't happen for a mother/child dyad. We need to recognize those reasons - but when we allow the focus to be so narrowed down that those are our only focus, that's when it's most likely that people will be defensive about it. If we can instead broaden the conversation to focus beyond the individual situation (i.e., Mom says that she had a low supply and dried up when she went back to work) - and talk about what we as a society need to do to change that (i.e., longer paid maternity leaves, better breast pump legislation as Senator Mahoney is trying to pass, workplace support of time for mothers to express their milk) .... then that's a bigger picture.
The formula companies try to keep the focus narrow. When mothers (naturally) look at their own perception of their success breastfeeding/formula feeding, then it's easy for the perception to become that criticism of formula vs. breastmilk etc. is a criticism of them, rather than a criticism of a larger social construct which needs to be changed.