So what is the fear among religionists first, well one is that getting into mediumship is met to be communicating with demons. Which is not true but they see as the work of satan. Now let's get to the fear among mainstream scientists that they would have adjust the laws of physics, and the worldview itself to either a dualistic one or idealism. It has been shown that evidence in support of an afterlife can be objectively looked at, that is why the argument that is used by skeptics that you cannot gather scientific evidence for an afterlife is false. Now let's get to psi phenomena yes the results are very weak however are persistent and won't go away. This is consistent to with the survivalist interpretation because if psi is very weak which experiments have shown though robust makes super psi more unlikely to account for survival evidence.
Here is a link to a blogpost by Dean Radin showing the fear among religionists and Mainstream scientists when it comes to psi phenomena and related phenomena like survival.
Here is an interesting comment made by Gareth on Dean Radin Blog
Some people feel that they are making the braver choice by basing their lives only on what the scientific mainstream has presented to them as fact. People who don't feel the same way are delusional kooks.
Some people feel that they are making the braver choice by basing their lives on challenging orthodoxy and exploring the possibilities that might exist on the fringe. People who don't feel the same way lack imagination and are frightened of the unknown.
Some people just live in the moment.
None of these differences are worth hurting another person over.
I agree it obviously does come with a heavy price to challenge mainstream science.