We are childless, not by choice.
We have been very fortunate to have many friends and family who have very generously shared their children with us over the years.
I would never put yard work above watching my child, or any child for that matter, participate in something.
I can remember how happy I was to have at least one, and usually both, of my parents at my events...my father was apoliceman, so on occaison his schedule did interfere, but I can only guess that he did a lot of switching of shifts and so forth, because he didn't miss too many of my or my brhter's events.
Years ago, we were the primary cheerleaders for my nephew, age 5, when he was participating in T-Ball (which is really what Dante had in mind when he described Hell

) because his parents were coaching his older brother's little league team and the two things occurred at the same time. Watching T-Ball is like watching paint dry....s l o w l y. I believe another poster described something as "monumentally boring"...that would fit T-Ball to a "T", if you'll pardon the pun! Amazingly enough, that young man, who is now 24 and applying to med school, remembers that and actually told his girlfriend how happy he was that Auntie Patty & Uncle Terry were always there for him when he was a kid playing T-Ball because he "knew it was probably boring, but they were there anyway". At the very least, I figure he'll pick me a nice nursing home.
It is quite true that I don't think grandparents and other assorted relatives need to attend every single thing a kid does. But it is nice if they attend some, and try to find something positivie to say to the kid.
It is not acceptable to play favorites, and that "outdoor plumbing" comment is unconscionable to me.
You know, with how screwy so many kids are today, would it hurt them to know they have a lot of people who love them? I don't think so. After all, don't we all like to show off our accomplishments a little? Kids are no different.
OP, I have no advice for you other than to have no expectations that these people are going to change, because they won't. I also wouldn't try and force a relationship or respect that isn't there. And I would be so bold as to say to my FIL, if he made commentary about how my DD didn't speak to him or "respect" him properly when she was in his presence "Well, since you essentially ignore her, I guess she learned that behavior from you".