1,) It’s history:
Wicca is a fertility religion. The fact that “Blessed Be” stems from a ritual referencing sex and fertility should not be surprising. But for those who do not know where the phrase stems from, it comes from this ritual called The Five-fold Kiss:
“FIVE FOLD KISS FEMALE
The High Priest kneels before the High Priestess and gives her the Five Fold Kiss; that is, he kisses her on both feet, both knees, womb, both breasts, and the lips, starting with the right of each pair. He says, as he does this:
“Blessed be thy feet, that have brought thee in these ways.
Blessed be thy knees, that shall kneel at the sacred altar.
Blessed be thy womb, without which we would not be.
Blessed be thy breasts, formed in beauty.
Blessed be thy lips, that shall utter the Sacred Names.”For the kiss on the lips, they embrace, length-to-length, with their feet, touching each others. When he reaches the womb, she spreads her arms wide, and the same after the kiss on the lips.
FIVE FOLD KISS MALE
The High Priestess kneels before the High Priest and gives him the
Five Fold Kiss; that is, she kisses him on both feet, both knees, phallus, both breasts, and the lips, starting with the right of each pair. she says, as she does this:“Blessed be thy feet, that have brought thee in these ways.
Blessed be thy knees, that shall kneel at the sacred altar.
Blessed be thy phallus, without which we would not be.
Blessed be thy breasts, formed in strength.
Blessed be thy lips, that shall utter the Sacred Names.”For the kiss on the lips, they embrace, length-to-length, with their feet touching each others. When she reaches the phallus, he spreads his arms wide, and the same after the kiss on the lips.“
Even if you don’t realize you’re referencing this, people can be reminded of it simply by you saying “Blessed Be”, and it can make them uncomfortable. In this case, listen to them and don’t fucking say it.
2.) They are uncomfortable with unsolicited religious blessings
Undoubtedly, Blessed Be is a blessing tied with religion. People who are not part of that religion, or are without religion completely, may not want to receive any sort of blessing from a religion that is not theirs. Same goes for people who say “God bless” to those who are not of an Abrahamic religion (since God inevitably is tied to YHWH in the west). This is just rude to do
3.) Its ties to the Wiccan God and Goddess
Like the “God bless” example listed above, many people associate “Blessed Be” with a blessing from the Wiccan Lord and Lady.
If someone is dedicated to a deity, and only wants interactions and blessings from that specific deity, then the blessing of deities from another pantheon would be unwanted and intrusive. This can be supremely annoying when one wants NOTHING to do with the Wiccan Lord and Lady.
So if someone says they would prefer you not say “Blessed Be” to them: listen to them. They’re not being “Wiccan-phobes”. They likely have a valid reason to request you refrain from blessing them. Just fucking listen to them
And remember, a secular blessing like “have a nice day” works just fine.
(I’m not meaning to remove any impact from your post, I agree thoroughly, just adding my own points.)
Saying “blessed be” outside of the ritual context is something that shouldn’t be done, because it is ritual-specific. It is supposed to be like a “sacred saying,” and using it willy-nilly can remove its sacred and ritualistic impact for Wicca.
It was meant to be used in the context of rituals such as the Five-Fold Kiss and initiations; it was not meant to be used as a general greeting or blessing to anyone and everyone. To be fair, it shouldn’t even really be said to non-Wiccans at all.
I understand wanting to wish someone well, that is not the problem we have with “blessed be” – the fact is, it equates to a specific ritual that many find uncomfortable, some people do not wish to be blessed by any deities (at all, period), and it is a ritualistic term that should not be used out of context.
If you want to wish someone well, [there are many alternatives to do so] that are not religious or invoke deities, invoke images of a rite that leave some people very uncomfortable, or remove impact from ritualistic sayings.