The objections I have read are:
1. cant digest cellulose
;;;I am not eating the whole plant, plus I probably could use a bit more fiber in my diet.
2. Wild things poop.
;;; I also eat other things like herbs and lettuce that are subject to said poop. There is a spot that I can pick grass that I am certain the birds don't hang out, namely a under leaning concrete wall that my cat sleeps on.
3. Spray ;;; I have a reel mower and I never spray my lawn
4. Oxolic acid
;;;This is what concerns me, I am not fond of the supposed side effects of this stuff. But it does not taste like other things that are high in oxolic acid. In the chalky mouth feel way.
;;;again, I eath other "normal" greens that would be subject to the evils of nature. Plus I dusted my property with safe mycorrhizae
6.Dogs pee there
;;; I don't own a dog, and I am not aware of any feral dogs here. Plus I doubt a small amount would cause any harm.
;;; Again everything I eat would be subject to that.
Also I tried a glass worth, and it had a refreshing, not unpleasant taste and my gut gave no complaints.
Any other thoughts of what I should consider?
Sounds like the risk (cyanide in non-native varieties) even as low as it is, isn't really worth it since the grass is so low in food value. (See link) That said if you can verify species, juicing may be a way to add extra chlorophyll to your diet. I wouldn't worry about oxalic acid, or any poo/pee residue if you give it a quick rinse.
I have juiced grass to experiment with the liquid as a fertilizer. I've not consumed it. I found the flavor unappealing.
Wheat grass is another story. Blending the juice from wheatgrass with juices from other plants produces a tasty drink. I picked up Stainless Steel Wheat Grass Hand Juicer a couple of years ago and started to experiment with it. I found that much more than 25% wheatgrass juice gave me the runs and I moved on to other projects.
I've been wondering if common lawn grass species are edible myself. The three common turf grass species native to North America are red fescue (Festuca rubra), buffalo grass (bouteloua dactyloides), and St. Augustine grass (Stenotaphrum secundatum). Buffalo grass is grown mainly in the plains states, red fescue is grown in the northeast, and St. Augustine grass is grown in the southern United States. Although no native grass has cyaninde in it, suburban lawns often incorporate alien turf grass species that might have cyanide in them. Some common turf grass species not native to North America are Kentucky bluegrass (Poa pratensis), bermuda grass (Cynodon dactylon), perennial ryegrass (Lolium perenne), and tall fescue (Festuca arundinacea). There are several other non-native and native turf grasses used in suburban lawns in North America so this list is non-exhaustive.
Since a lawn may be more likely to have a non-native species of turf grass on it than not, I would suggest researching what are the common turf grass species used in your region and if any of the species contain cyanide or have a tendency to accumulate nitrates before deciding to juice them.
Mandrake...takes on and holds the influence
of the devil more than other herbs because of its similarity
to a human. Whence, also, a person’s desires, whether good
or evil, are stirred up through it...
-Hildegard of Bingen, Physica
Many of the lawn grasses aren't a wise choice for juicing, the reasoning is that most "Lawn" grass species contain compounds that are not particularly good for the human body.
Don't get me wrong, in small quantities they might be ok, (a lab test for toxins would be a great idea prior to giving the grass a trial inside your body).
The question is, is it worth that risk? If the answer is yes it is, then go ahead, but do try to think about any possible consequences.
Investigation of what those plants contain is never a bad idea. I look at things like this from the POV of if this was a mushroom, how would I go about making sure it is safe to eat instead of making myself sick or dead on a whim.