system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a point at which philosophy becomes to dangerous to be considered “respectable?”

I am just wondering if since ethics is something philosophers don’t agree on, is there at least a minimum level of civility or tolerance required to practice modern philosophy?

So, let’s say a modern philosopher were to build upon Thomas Aquinas’ view that heretics (from the Catholic viewpoint) should be killed if they do not refrain from teaching against the faith after admonition. Thomas is obviously a well respected philosopher who is treated seriously, but this view is not one you are likely to see in modern philosophy. But, if someone did seriously bring it up and actively promote some system thorough which those in conflict with the church are killed, could this be considered serious philosophy today? Or is there a minimum standard (don’t promote the killing of people who disagree) of conduct required to practice professional philosophy?
gpt
I think philosophy can be regarded as serious no matter what it argues for, so long as it uses rational arguments to advance a position and not just raw ad baculum.

I don't that people deny certain positions because they can't be held in "serious philosophy", but because people culturally no longer accept the premises that that make certain arguments sound. To take your Aquinas example, here is the argument summarized from ST.II.II Q.11 A.3:

If the state has an obligation to seek the good of its citizens including through the coercion and execution of those convicted of crimes (A),  and believing in specific doctrines are the only  way for those citizens to achieve their greatest good (B), and if heresy is a crime that prevents those citizens from believing specific doctrines (C), then it seems the state has an obligation to execute heretics. (D)

1. A\^B\^C --> D
2. A\^B\^C

∴ D

Now on the face of it, it seems that D does actually follow if A,B and C are true. But today almost everyone denies at least one of A or B or C, and so almost everyone now denies the soundness of this argument. But in Aquinas's time almost his entire audience would have been on board already with all three and so this argument would likely have been persuasive.

And of course in academia there are certain positions that can't be publicly advocated because of cultural pressures, but this doesn't mean that these positions cannot be seriously defended philosophically. Hume's writings would not have been allowed in the universities during the time of High Scholasticism, but this doesn't imply that his philosophy is  not serious.