I would not say anyone has been encouraged. Certain users (unnamed) are on their last warning - we prefer to try and just keep things civil and educate, rather than having to ban.
If you genuinely feel that a post is offensive, you can flag it. That's how this community (and all of stackexchange) chooses to do so. If enough offensive flags appear on an answer, it gets automatically deleted. If not, the downvotes come into effect - enough downvotes, I guess, may shame the person into deleting it (there's even a badge for deleting -3 answers). Not always though, and that's their right. It's about a community coming together to find the best answers, not censorship.
Saying that, there are and have been some times when a post has been over the top, ridiculously offensive - vulgar language, or even just insults and name calling. Many people (yourself included on one of those answers you link to) have had warnings about not doing this, and we'll sometimes delete them for this.
If there's a disagreement, it's stackexchange's protocol to take it to the chat room, not putting it in comments on the answers. That's not our (moderators choice) - it's Stackexchange's guidelines. Some being offensive in posts have not even realised they were doing so (language barrier) until they discussed it with us in the chat room.
The reason we say this is that this site has 3 part-time volunteer moderators. Fortuitously we're in reasonably different timezones, but we still can't spot every single answer, or comment. Things slip through. Hashing it out with others in the chat is often handy - there's usually someone in there - be it Doc, hippietrail, Roflcopterexception or another of the regulars. Failing that, you can flag it.
As for incorrect information, well, especially legal stuff (which is one reason we kept immigration stuff off topic), mods can't know every single thing. So then the community has to come into it. If someone disagrees with your answer, it sucks, but they may downvote it. Incidentally your one today on visas - @Doc explained in a comment why he thought it was wrong, which I spotted - which is why I asked either of you to provide sources - the only reliable way of settling what at that point were anecdotal statements. I do think more people providing sources would go a long way. Doc's updated his answer on that question, with sources, might be worth taking a look and see what you think?
As for Israel, I get serious tension any time I see a question involving that country, just because I get nervous it's going to kick off a flame session ;) As best as we can, we have to tread the line between censorship and preventing insults, hate messages or whatever. However, while we don't intentionally leave them up, we may miss some. Again, please flag them, or come into the chat to discuss, if you feel they're not being dealt with properly.
It's a travel website, and what this means is you're bound to have culture clashes, language barriers and more. Far more than you'll get on english.se, or programmers.se or fitness.se. So yes, there's probably more heated debates, but from some discussions in the chat, others prefer it over English.se for friendliness(!).
Similarly, English.se is not likely to be discussing legally dubious activities. And some people on travel may even do this unintentionally - laws change, so someone speaking anecdotally may have had a different experience - laws could be different when A went vs when B went. (one of the reasons I like citations).
Finally, with reference to the people you called out, I don't have the time right now to check everyone's history to determine if there's a downvote war, and I'm not inclined to start a witch hunt. One of the links you mentioned actually has a downvote where a user (none of the ones you mentioned) said it was him and his reason too.
I do feel that politics causes problems way too often on here. What's the solution? Censorship? Outright banning of certain phrases? I don't know. We've been talking about having a townhall meeting, and this is probably going to need to be one of the topics. We've added it to the [faq], but funnily when people are worked up about something religious/political they seem to not usually stop to check the [faq] :(
Moderators are to try and keep things civil, but not to censor. It's a narrow line though.
As someone who feels Israel DOES exist, personally, I also dislike it when someone disagrees with that. But as long as they keep it civil, I have to respect their point of view. However, they have to respect mine too, and as this is a travel site, as long as you can go out and buy a train/bus/plane ticket to Israel, travellers are going to be asking about it.
I have good days and bad days on here too. This week I've had a new user commenting repeatedly that I should accept his answer with my bounty, in a rather...curt manner. The day lejohn started deleting everything he wrote was terrible. But other days you write a great right answer and make someone's day. And those are the days that make it worth it.