>cruise missiles and ballistic missile

No I'm not, I distinguished between the different ordnances and known interception probabilities, as known as what info is publically available if one follows the space. Cruise missiles / TLAMs / tomahawk equivalents, aka subsonic munitions, not ballistic mach1-<mach5 or >mach 5 hypersonics, are "easy" to intercept. Even with 30 year old Russian hardware, S200-300s (as seen against US tomahawks in Syria). Older platforms shot down U2s 50 years ago, they can shoot down cruise missiles. Indeed all of those were shot down along with subsonic drones. Likely garbage subsonic drones, without any stealth shaping nor TERCOM/terrain hugging. Which is expected. What penetrated was ~10 ballistics, out of 50/100 depending on dud rate, ~10-20%. That's really the new revelation, we only know from past 10 years US FTM tests that missile defense has consistently intercepted against 1-2 < mach5 ballisitcs, but couldn't extrapolate at scale.

Now we know againt allegedly crude Iranian ballistics (if dud rate true), with forwarning, 10%-20% made it through. Which is a great number mind you relative to where we were 10 years ago, but it's also pretty terrible stats with respect major assets like carrier survival. Or in IL case, IR calibrating future attacks to satuate defense. People see 80%-90% ballistic interception, are thinking missile defense strong, which it is true relative to powers that can't coordinate large strike packages (which granted is most of the world), but people who see 10-20% ballistic penetration see dead carriers and MIRVs deliverying nuclear payloads.

>300+ is more than was fired in a single attack against any country ever.

Coalition air strike during Gulf war hovered between 800-100 sorties per day, with planes carrying multipe munitions. Thousands of essentially uncontested fires. This is the first time a "decent" size salvo was directed at western missile defense. 300 mixed salvo is small, even smaller since we're really talking about 50-100 ballistics. Like US sent ~100 tomahawks against IIRC 3 targets in Syria with fraction of anti missile coverage. AKA even against shit tier Syria, US weaponeer were throwing 3 digits to shut down a few targets. Hence IMO 300 mixed ordnance against IL who is definitely 3x more capable than Syria capabilities is "calibrated" not to be big. Like IR probably expected more to penetrate, but just demonstrating a strike package like this was enough penetrate western/IL defense is enough, even if west wants to spin it as embarrassment.

>Calling it small is disingenuous.

It's small in the sense that 50-100 ballistics is close to floor of what modern anti missile defense networks are designed against, i.e. a loaded carrier group with 5-6 DDGs ~500 VLS tubes is designed to intercept 100s of ballistics. 50-100 ballistics maybe substantial relative to Iranian capabilities, but it's small relative to missile defense capabilities western (well US/IL) hardware is designed for. For reference PRC H6 salvo against a carrier group would have 200-300 antiship ballistics. Double that with hypersonics from land. That's what a large salvo a dense missile defense network is calibrated against. Another comparison, estimates of disabling PRC bases in SCS is like 300-400 tomahawks for just major installations on Spratlys and Woody Island. So measured against targets with less missile defense density than Israel, with forwarning, and assistance, the 300 ordnance mix IR planned, of which only 100 had serious chance of penetrating, is indeed "small".

> was done rapidly at a relatively short distance

By distance I think you mean terminal interception which is the easiest/most technically mature form of interception, but generally missile defense wants to move away from terminal, to more difficult midcourse because terminal is constrained by prepositioning of hardware, which since Israel is small is less of an issue. If anything because Israel is small, it has disproportionate density of sensors and overlap in shooters coverage. Like it shouldn't be controvesial to suggest Israel has the densest anti missile coverage in the world. More than most carrier deployment only gets 1-2 DDGs escorts - 180 VLS of which only a fraction is dedicated to missile defense. Israel small size = almost any hardware in it, is within interception range, especially considering they'll be prepositioned against IR direction. IMO that's really how this event should be interpretted. How the geographically densest and most advanced missile defense network in the world allowed 10-20% of ballistics from sanctioned country with limited industrial base through.

>has enough missiles the volume doesn't matter

Which is really crux, this is the unknown unknown territory. If IR missiles penetrated, either 10/50 went through before IL ran out of inteceptors, meaning IL only had enough inteceptors for 40-80 or so ballistics, or interceptor performance is 80-90% effective. Either way, IR showed it can penetrate IL missile defense with pretty medioore hardware (again relative to what missile defense is designed against), without hezbollah running interference. It's not a win in the sense that they probably expected more damage, but it's not a loss either considering what it revealed about current state of the art missile defense and the implications there of. Like PLA bomber/rocketforce weaponeers are adjusting their spread sheet formulas. Question is which direction.