What exactly do you mean by a defensive party? I know you're using a hyperbole, but obviously no one really thinks a team full of nukers is going to get them through the game. If there were ever people that actually thought that, they'd learn very quickly that its not possible.
By defensive party, I just mean one with more characters that are known for 'being able to take hits', than those who are 'squishy'....and actually, most people have expressed over the years that glass cannon oriented parties are better. I'm not talking about 100% glass cannons without a single tank. But lots of people seem to think you only need like 2 tanks and the rest glass cannons...and by only need, I mean they think that's the flat out superior party makeup.
So they'll have a party with an inordinate amount of squishy nukers like chen, and nitori (she's not especially squishy but she's not really 'can take hits'y either in lot1), and aya, and kaggy, and yuugi (obviously tanky on physical bosses, but the vast majority of bosses have decent aoe magic nukes, or random target magic nukes), etc.
They also have little appreciation for damage dealers who have higher staying power like remilia, eiki, I wanna say kanako but she really is bad at dealing damage lol...not too many come to think of it, I kinda put patchy in here too. She's kinda like yuugi but there are far less bosses who can abuse aoe physical nukes than those with magic, so patchy CAN be pretty stable in the back against bosses unelss they have needle parade or arrow rain.
It's not just about which character though... most people also think that you should just always pick mag/atk for level up bonuses on anyone that isn't a tank or support. They would NEVER make a mnd build patchy, or a def build remilia, etc...they think they can't do damage if you do that..but they certainly can, and the benefits are actually really good. For example, a mnd build patchy will take 0 magic damage from virtually everything (even kedamageddon's ultimate nuke if you put necronomicon on her too... Ia ctually beat it by having patchy SOLO it and take 0s all the time), and because silent selene has good mnd piercing, her damage does't get neutered THAT much against bosses with reasonable mnd defense. Similarly, a mnd build eiki is good because her nuke pierces completely, it will not do that much less damage, but she'll become quite tanky.
Even kaggy makes a good mnd build I think because buddha's stone bowl is potentially just as damaging as her spirit nuke, moreso even if used on someone like nitori or suwako against yukari or whatever, and it doesn't benefit from mag at all. So mnd kaggy can ALMOST be as tanky as patchy against non-physical bosses (btw you may think most bosses can snipe the back with a physical nuke like slash or regular attack, they can, but even patchy can take a hit like that due to back row mitigation. 'snipe', and the odd back target 'double slash/steel slasher' are really the only attacks I can really think of that will waste em, but those are rare as fuu (well back targeting slashes I mean).
Not really sure how that's hyperbole though.
Heck, I also see people express how useless they think ran's defensive buff is compared to her offensive one. I think they are both great. With her defensive one, it allows you to have a character out with a defense buff. But without it, if you rely on reimu or yukari or someone, you have to go thru the trouble of making sure they get just before reimu can buff, and that she can go before the boss can nuke, which can delay you a few rounds fairly often if you want to play it safe.