I am legitimately asking this, say maybe I think that X feature is nature not nurture, and there is a discussion at an event about X , what do I Google to know if I should talk about X or not. The problem is more complicated if my opinion today would be controversial in the future.
There are no such guarantees (much as there are no guarantees in the tech space... That, say, your favorite language today won't be obsolete in five years and therefore diminish the value of all the time and effort you invested in memorizing its quirks). There are some useful heuristics, such as "try and be a good person, minimize your judgement of others, avoid speculating on things that other people have concrete experience with." Also, be informed about the latest social media culture; Proposition 8 was huge in California (and around the U.S.) and it should have been self-evident to Eich that supporting it was a bad call (I'm a lot less forgiving of Eich than some people are, because it's real hard for me to see his behavior and interpret it as anything other than "He put money behind his convictions and mis-estimated how much political power homosexual people and their allies had in his company to hold him accountable to putting money behind his convictions," which isn't exactly a stellar review of his behavior).
We in tech seem to like to believe that the technical world is above politics. It's not; technology serves people, so politics is, of course, part of the story. Politics is just what happens when people interact.
"I should always speak in an uncensored fashion" is, honestly, one of the poison memes of the modern internet. It's never been wise in any human interaction, and moving to the Internet didn't change that fact. It did, for a brief time (until de-anonymization and search caught up with the technology available) let people obfuscate opinion origins behind a sea of anonymity and momentarily disrupt the words from the responsibility of having reputation tied to them. But when you go looking at the most anonymity-enabling communications channels on the Internet, you don't exactly find humanity at its best. Words divorced from reputation have yet to be proven as a net positive. Hell, even on Hacker News, our handles have karma points attached.
We social creatures developed concepts like "reputation" and tools like "memory" for a reason, and it wasn't a bad reason. Like any tools, they can be abused or over-applied, but no; saying exactly what you think all the time isn't virtuous (it is yet another tool, which can be abused or over-applied).
The internet is not just a place for meeting people and discussing opinions.
For many, many people, the internet is a socially supportive space, and an activity space, and those things don't work if challenging discussions are constantly taking place in them.
For what you've just asked for, specifically about making arguments that might change your mind, may I suggest you might enjoy: https://www.reddit.com/r/changemyview/ and https://changemyview.net/subreddit/ (I haven't used them myself, just read about them.)
I think the fact it occurred to you to ask, suggests an answer. If you would feel safer testing the water with a different account, then I'd recommend you do that.
People have an annoying habit of attributing expressed thoughts to a person long after the person has openly changed their mind, as well as misunderstanding the intended meaning of a stated view anyway. Same if the person was just constructing an argument for the purpose of thinking things through (for example as in devil's advocate).
Personally, I would also recommend a "listen first" approach.
Eich didn't get forced out for having a "bad private opinion;" he got forced out for supporting something materially that would cause material harm to Mozilla staff, then making clear his opinion on the topic was unchanged. Staff that had a lack of confidence in his continued leadership were entirely justified.