I think the introduction of the idea of being welcoming was long overdue and the delay allowed righteous and punitive patterns of behavior to crystalize in some people and in some areas of SE, but I welcome it wholeheartedly.
The more times and the more ways we remind people of the importance of being welcoming, and that we should pause a moment before reacting to new users, the better.
The nature of SE allows people to move freely between sites, so there isn't much one can do about silent, anonymous drive-by down-voting, as I've been reminded here about the related phenomenon of drive-by close-voting.
SE's "welcoming reminder" (for lack of a better term) mentions "asking for clarification, commenting, and answering" but conspicuously avoids mentioning voting. That's probably been thought through carefully, and I come to the same conclusion.

(user) is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
There's probably no practical solution. SE schemes like weighting down-votes at 50% for new users until the first time they hit reputation=50 are impractical.

Countering harsh down voting of new users with questions that appear to be good faith efforts by up voting, is all we've really got at the level of individual questions (the impact of leaving a "don't down vote" comment is unpredictable (example of such on similar +3/-4 voting)). Side effects of countering down votes with up votes are
- net increase in rep for the user
- one step towards the user getting "in trouble" for having too many down votes too soon.
Both of those have positive and negative aspects.
answer: Yes. People shouldn't do it, but some will. We can slow that down by continuing to spread the message. One way you can do that is by up voting the question here if you agree with it which is the quick way to answer a meta question in the affirmative.