In the cases where the problem is fixed, I think you'll find that the explanation is as simple as this:
They view the message as showing up a failure on their part and they do not want anything showing that they have made a mistake in some way. So, they do not acknowledge your message as it provide a means of tracking that failure.
For those cases where it is not fixed, there is no-one who cares to do so.
In the past, I have made communications with website admins about various aspects of their sites (non-security related) when they poorly relate to those of us who are getting older and have increasing eyesight difficulties. The usual response has been "No one else has complained, so take a long jump off a short pier - our site is perfect." I sometimes try to explain that people won't continue to visit if the experience is bad, nor will they bother highlighting that there are problems. They will generally still respond with "shut-up and go away."
You just leave them to their ineffective site and move on. Very occasionally, you get back a thanks and see improvements made, but that is rare.
They view the message as showing up a failure on their part and they do not want anything showing that they have made a mistake in some way. So, they do not acknowledge your message as it provide a means of tracking that failure.
For those cases where it is not fixed, there is no-one who cares to do so.
In the past, I have made communications with website admins about various aspects of their sites (non-security related) when they poorly relate to those of us who are getting older and have increasing eyesight difficulties. The usual response has been "No one else has complained, so take a long jump off a short pier - our site is perfect." I sometimes try to explain that people won't continue to visit if the experience is bad, nor will they bother highlighting that there are problems. They will generally still respond with "shut-up and go away."
You just leave them to their ineffective site and move on. Very occasionally, you get back a thanks and see improvements made, but that is rare.