Due to lack of any decent ranged units early-game, Zerg cannot realistically break through a blocked choke; The only valid strategy of rushing against a walled opponent(note: almost every opponent) involves sacrificing banelings on buildings, which means that you effectively waste multiple(at least 8 if you want to break anything) 50 mineral 25 gas units to break in, and THEN you get to fight his army with yours. Now you must be thinking: you better be damn sure that your army after banelings > his army if you are investing ~ 400 mineral 200 gas just to be allowed to fight army vs army, but you can never be sure due to the following point.
As a zerg, neither of the other two races are scoutable if the opponent puts his mind into not being scouted. This is because... the other two races have early, yet very solid air-attacking units(marines, stalkers, and sentries). These units, being... units, are never wasted(unlike stationary defense structures) and can combine with your army at any time while preventing any overlord from scouting. A terran has insanely rigged scouting capabilities; There is literally zero way of stopping a scan from happening, and terrans have an access to a 1000 hp overlord that flies faster(a barracks, for the slower people), yay. A protoss has equally difficult time scouting terrans and other... protoss, but at the very least you won't get surprised by "air-rush" as easily because no matter which path you took, there is anti-air built in with your army(stalkers and sentries with warp gate for instant additional stalker support if you went ground route, if you went air route... yea... everything you built can attack air).
A zerg has... zero way of stopping scout from happening from any race. You can't block your entrance with buildings, due to the creep requirement(not that you would even want to anyway, seeing as how zerg buildings have the slowest build time, you'd have to leave a gap for your own units to pass through, and god help you if you want to put zerglings in that gap to get mass massacred by a single zealot), so your only option if you want to have the same super secret base is to block off your entrance with units. Now, let's say you blocked it off with 6 zerglings(if you block it with roaches or any greater number of zerglings, you've already done the scouting for him) a terran can obviously bypass it with the scan or 1000 hp, 150 mineral overlord that flies faster, as mentioned above while a protoss can spend 200 minerals to stomp the lings and get inside to see base or army(again, stopping these zealots would involve showing him your army, which is the whole point).
TLDR: Please give the zerg an access to build a flying building like barracks for 100 minerals(the drone would be consumed, making it same as barracks in almost every way) so that they can scout the others as easily as they can be scouted. It is extremely frustrating to see terran and protoss blocking their entrance off while seeing what I'm doing at any given moment should they wish to. I just want the 1000 HP overlord to scout around instead of a larvae-consuming, 100 minerals, slowest-unit-in-the-game scout.