Firstly I am new to the forum so and secondly I imagine the issue here is to do with the
<meta name="viewport"> tag. This tag can be used to disable pinch zoom and magnifying even though it causes the accessibility issues we are experiencing here.
I can see that on this forum this tag is set to
<meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes">
If you have access to this all you need to do is change this to be
<meta name="viewport" initial-scale=1.0"> and this should allow people to zoom as much or little as they want.