RuneScape dating has been around for a long time and sadly is still around. RuneScape dating isn't against the rules, but Jagex is strongly against it. However, going on public chat asking for a boyfriend/girlfriend is considered against Rule 1 and you may be muted.
RuneScape dating can cause many problems that can be avoided. The main issue is that there is no point. You can't get married, no matter how many times most people who practice RuneScape Dating try to kid themselves. Another, more unadressed reason is the unbalanced genders the person on the other end of your chat could be acting female but infact is male. Sometimes, some male players try hard to get the attention of a female players, sometimes by constant messaging and other times giving them expensive items. Lastly, RuneScape is a game, it isn't a match maker or anything like that. You play to have fun and meet new people to have healthy relationships, not do the stuff you should do in real life.