Not a problem, because they could be a teacher or boss or something, a pastor, community leader. People need to stop viewing one another "that" way and start viewing each other as another person God loved first, so much that he gave his only begotten son, Jesus, for them, for their GOOD life, that God is FOR them, not against them, and would not want them to be harmed, treated impurely, unjustly, or otherwise wrong. It shouldn't even come to mind, other than if some person asks, Hey, why are you friending so-and-so. Then you deal with THAT person's religiosity and impure thinking in a kind way, and pray for them. Don't you dare pass up a chance to improve your thinking because someone has a worry about "how it looks". It looks to ME like God put people around people or allowed it, and will take care of any and all issues. If you think someone can only learn from or work with the same sex, that is a problem! There are parts of our brains that won't work unless we learn from people who are biologically different than we are, who are more intelligent in different kinds of ways, who are gifted in different ways, etc. Timothy exhorted us to learn from EVERYONE. Okay, there was a context, sure :) But check it out: https://biblehub.com/esv/1_timothy/4.htm
The only people who cannot adhere to this type of thinking yet (and I'm trying trying trying to be kind, not insulting, because I know everyone has different issues, different pasts) would be someone who has not worked through all their issues in how they view other people. :( If you view someone like they are a means to an end, a product and not a PERSON, a thing to check off a list, etc., then that is where some of the problems come in. If you spend an inordinate amount of time thinking about people in terms of how pretty or beautiful they are, and not how well they speak about a certain topic you need to learn more about, or just plain value them in the first place, then that is where problems come in. A giver wants the best for someone (the best that they're aware of, in general, even if they don't know them--meaning, nothing to harm them, their goals met, nothing personal; when it's not a stranger and an actual friend like offline, people you go to church with are a little different than who you bumped into at McDonald's or someone who runs an online business. But you don't think less or more of them, you just aren't as aware of all that is "best" or what they want, just that GOD's got a best for them, and it doesn't include allowing people to say rude things about something that should have been a non-issue in the first place.)
I have never been afraid to have an opposite sex online acquaintance or offline, but use WISDOM about it. So not someone with Adadadasads :LKJ::LKJ:L:KJ name who DMs things to me, but smart and wise Godly people? That is okay. They are not going to DM me something wrong if they ever did DM in the first place. I have traditionally been more nervous about same sex online acquaintances for a variety of reasons, a main one being they tend to get me talking, then take my ideas, make fun of me, abandon after alienating me with others, then use my ideas like it was some awesome thing. Or they do other stuff like immediately DM their business without "Hi, how are you?" and then do the same to the rest of my friend list!!!! Because they are desperate and not working hard or smart. They are treating people like objects.
We can't treat people like objects and then expect the world to change.