Huh? The connotation is strong enough that it is relatively common for dictionaries to state that the word actually denotes intent, beyond connoting it.
Um, as the links I’ve established show, most dictionaries do NOT include intent as part of the definition. Violence, yes, but intent, no.
There is no argument that most dictionaries suggest that “slay” denotes intentional killing, but a significant number actually do.
Nobody in this thread is arguing that the word has this literal meaning, but it is certainly an indication that it has acquired the connotation.