Suppose we were talking about some other unethical thing. Let's use Amazon as an example.
Amazon is unethical, for the purposes of this discussion.
There's a thread on MN where posters are discussing Amazon, including many who boycott it. Someone, we will call her GlamourPuppy, joins in to say, 'I have to use Amazon because I'm disabled and can't get out of the house, and I buy my incontinence pads there.'
On the face of it, this is reasonable. If you're incontinent, you need hygiene products. Maybe not as obviously essential as food, but pretty important! And you use whatever you can to access them.
Some poster, let's call her Guilticenta, objects to this and says, 'Are you sure Amazon is really your only option for that? Maybe you could try ordering them through a local pharmacy? Or direct from the brand you use?'
GlamourPuppy is very angry with Guilticenta because GP feels that she is talking about something essential, and so this shouldn't be challenged.
But then it emerges in the discussion that GlamourPuppy is also using Amazon to buy false eyelashes, and single use razors, and fake snow at Christmas, and and and... So actually, it seems like GP just likes to shop on Amazon. It's not about getting one or two essential products there. And in that case, why did GP initially present herself as having an experience relevant to a thread about living ethically? (In this instance, boycotting Amazon.)