Quite right a bit on the start, you do make some points regarding Japanese shows, but when you state you think Ike and Soren to not be friends...well. I'll point you to Naruto's and Sasuke's relationship in aforementioned series, now I'm sure you know how many fanfic and art stuffs are drawn of the two being homo for each other, as you yourself have revealed your bias for thinking Ike to be gay by stating you would like to write fanfics. You said it yourself. "Perhaps it was to make them fans to go crazy and write fanfics." This itself is also shown heavily in Korean pop all male groups and Japanese visual-kei music groups, in both these genres there is a very big and notable emphasis on male members to display and do things on stage that would hint at something, while they themselves not being that thing themselves; like you said, it is for the fans, to like the group more. I disgress, however, see Naruto's and Sasuke's relationship and how there are fanfics and art about the two as lovers. They are very much indeed friends
, and yet Naruto goes extremely out of his way to "get back" Sasuke, i.e. "saving" him, it is because the two have a very strong bond. While your ideas of how friends should act, from your Western culture no less, may see two males as being gay just because they actually care enough about their friend enough to actually ask them and make them tell you what was wrong; this is not so in others.
What I'm trying to say is, in Japan, things like loyalty and extremely strong friendships are a big theme in series and culture, it is not uncommon for friends to go and do things above and beyond what normal friends would do. While others who were betrayed like Naruto by their best friend may forget about this betrayer and hate them, Naruto still insists on getting Sasuke back, so why would anyone want to do this for someone who betrayed them, because of the close bond Naruto KNOWS they had. Think of Soren as a Sasuke and Ike as a Naruto then you'll understand what I'm talking about a little bit more. And don't even think about arguing Naruto's sexuality, it's been shown repeatedly in the series, especially earlier in them that he had a crush on Sakura. Think about it, if you were Soren and Ike and his dad practically saved your life, on top of that becoming your first, best and only friend; would you just think of them as a regular friend or something more like a brother, it is because of that that makes Soren and Ike be friends as they are; and it is because that itself that people not familiar with Japanese views on friendship and loyalty instaneously think:
...Gay.