I think you are both right and not right.
I truly don’t believe May is coming in with any intent to hurt Walsh.
But I think the important part that makes this an illegal tackle, is that he doesn’t bend his back to make a tackle.
The duty of care sounds like a cop out, but in reality, he is the one making the decision to come flying out of the line, if he wants to make a big tackle, he should be putting his body on the line to do so, not putting Walsh’s body on the line to do so.
He never makes any attempt to actually make a tackle, he just looks to body check him.
If he bends his back and spears Walsh through the guts, it would be a highlight reel tackle that even we could appreciate.