See I don't know or care whether you're kill stealing with spectre dagon and it doesn't matter. The problem is that it's not your job. Every hero in dota has a role, some have many roles they can choose from. Spectre's role is not to deal 400 magic damage. Spectre's role is to be a massive lategame carry that fights all five enemies at once and cuts them down, before focusing in on a priority target and eliminating them. There IS a right and wrong way to play dota heroes. Not every dota hero is made equal, their abilities dictate their role for the most part. Spectre's abilities do not synthesize well with dealing magic burst damage, they work well for sustained attacking and high HP. Other heroes' abilities do.
It's like a Skywrath Mage building a Buriza and Assault Curias. Yes it technically works: you can attack with skywrath, you can deal damage with autoattack, and you can win plenty of games doing this just because people are bad and will lose to anything. Yet most DotA players would still not accept this build since physical attacks are not Skywrath's job.
If you want to deal magical burst damage, that's completely fine. I love dealing magic damage. So play Lion, Lina, Leshrac, Ogre, Zeus, or any other of the vast amount of choices available to you. Not only is it their job to deal magic damage, but they do it even better! You don't even have to spent 2600 to deal magic damage, you deal it right away and you can put that gold towards some useful items.
Some players were yelling and angry b/c a support player was farming in lane with him and he's all "I'm the carry! You are stealing my farm rawr!!"
The meta for serious games is that supports prioritize denying/harassing/protecting the carry, while carries prioritize last hitting. I'm not insanely optimistic, I don't expect this to happen in ENT dota.
If you're playing spectre, your job is to last hit. If you're not last hitting, you are failing your team. If you can't last hit properly, then you should not play a carry.