From a security standpoint, always utilize 2-factor authentication wherever possible. For example, if I am logging in to Facebook with a new device, after entering my username/password, it will text me a 6 digit code to my phone that I am required to enter before letting me in. The point of it is that even if someone knew your password, they would still need access to your physical device (i.e. your phone) to gain access.
This is not specific to Facebook either. I have 2-factor authentication setup for my bank, tax software, other social media sites, Google, etc. If you want to protect yourself from identity theft, using a strong password in addition to 2-factor authentication will keep you safe. Most sites are now offering this, but you have to opt-in to it (usually found in the security settings). Some sites now are even requiring it.
I've had a Facebook account for 17 years now and I've never had an issue with unauthorized access to my account. I personally use it to stay connected with my college classmates, as well as being in some really great groups (NCWW, an alumni group for my college, parents group for my sons' school, my neighborhood group, NC State Parks, laser engraving, and several other WWing groups with specific focuses like Bandsaw boxes, segmented turning, pen turning, etc.) The NCWW group is one of the best groups I'm in.
But to the point of the OP, there have been quite a few people that have joined the NCWW facebook group just looking to sell their tools. In some cases, these are not woodworkers, but relatives/spouses who are selling the tools of their loved ones who either cannot use them anymore, or have deceased. It is easy for them to post there as opposed to joining here and waiting for privileges to post in our For Sale forum (which is a semi-frequent Help Desk question). This post was highlighting that there were a lot of things posted for sale recently (and at pretty good prices)